SI-2881是一款2.4G、蓝牙(BLE 5.0三通道)和有线3模101键机械键盘。支持连接5个设备，有线模式符合USB 1.1版本及其以上版本协议,适用于各种PC端。2.4G和蓝牙符合ISM（工业、商业、医疗业）频段自动跳频要求，有效避免无线装置之间相互干扰的问题。2.4G和蓝牙传输10米无障碍可视操作距离。
- 时尚的外观设计，101键布局，采用Gasket结构与PCB单键开槽设计，提供细腻软弹的按键手感。
- 键帽和机械开关均支持热插拔，用户可自由选购市面上各品牌开关及个性化键帽进行DIY改装。
- 键盘用料扎实，按键反应灵敏。
- 配备两段式可调脚架，左上方铭牌处设有隐藏式2.4G接收器收纳仓。
- 可通过FN+\|组合键切换15种RGB灯效及关闭状态，共16种灯效模式：随波逐流（恢复默认后灯效）、如影随形、正弦光波、旋转风车、七彩瀑布、花开富贵、游戏模式、关闭模式、常亮模式、呼吸模式、梦幻彩虹、一触即发、雨中漫步、按键涟漪、繁星点点、川流不息。
- 配合专用驱动支持音乐律动RGB灯效，该模式下有10种灯效可选。
- 有线模式与2.4G模式下，配合驱动可实现全键自定义功能及宏定义，驱动支持自定义1600多万种颜色。
- 键盘采用人性化设计，与Fn键配合提供一系列常用快捷功能按键。
- 将右上角开关拨至2.4G模式，`~键青色灯慢闪；然后长按FN+`~键3秒，青色灯快闪进入对码状态，此时插入接收器即可完成对码，`~键青色灯亮2秒表示2.4G连接成功。注意：2.4G连接时需先进入对码状态再插入接收器，出厂默认已完成对码。
- 将右上角开关拨至蓝牙模式（BLE5.0/BLE3.0，设备名：K98 5.0/K98 3.0），键盘会根据终端设备的蓝牙版本随机广播，最多可连接3个设备：FN+1=蓝牙1通道，按键下蓝色指示灯，通道广播时蓝灯快闪，回连时慢闪，连接成功后蓝色常亮2秒；FN+2=蓝牙2通道，指示灯状态同上；FN+3=蓝牙3通道，指示灯状态同上。
- 将右上角开关拨至中间位置即为有线模式，此时4键上白灯亮2秒。
- 右上角三段式模式开关：左=蓝牙模式，中=有线模式，右=2.4G模式。
- 长按Fn+Space（空格）键3秒可恢复出厂默认设置，已配对的蓝牙设备不会被清除。
- Fn+↑=增加背光亮度；Fn+↓=降低背光亮度；Fn+←=降低背光速度；Fn+→=增加背光速度。
- FN+Q=切换至Android模式；FN+W=切换至Windows模式；FN+E=切换至Mac模式。
- 左侧设有独立CAPS大小写锁定指示灯，NUM键上方设有独立数字锁定指示灯。
- Fn+Tab=切换灯效颜色。
- Fn+左WIN=锁定/解锁左Windows窗口键（Windows系统下，锁WIN时锁WIN指示灯常亮）。
- 切换到Mac/IOS系统后，左WIN与左ALT键位置自动互换（该模式下WIN键锁定功能失效）。
- 配备RGB氛围灯条，功能如下：①FN+左SHIFT=切换右上角5个灯组成的Logo灯条灯光模式：流光-霓虹-常亮(默认红)–呼吸(默认红)-关灯；②FN+左CTRL=调节灯效速度，共三档，默认第二档；③FN+Z=呼吸及常亮模式下切换颜色：红-绿-蓝-橙-紫-青-白；④FN+B=进入电量模式，包含电量显示及充电灯效显示。RGB氛围灯条可通过FN+B显示键盘电量，充电时以跑马灯显示，充满后长亮绿色，低电量时全红指示。复位或重新上电后退出电量模式，恢复正常灯效。插上USB时优先显示充电状态。
- 配备侧灯灯效，功能如下：①FN+右SHIFT=切换5种侧边灯效：流光-霓虹-常亮(默认红)–呼吸(默认红)-关灯；②FN+.>=切换三档侧灯速度，默认第二档，循环递加；③FN+右Ctrl=切换五档侧灯亮度：灭灯-25%-50%-75%-100%，默认50%，循环递加；④FN+/?=呼吸及常亮模式下切换颜色：红-绿-蓝-橙-紫-青-白。
- 按住FN键可显示当前状态：3种模式键、3个蓝牙通道键、3个系统切换键下方均亮白灯，松开FN键后恢复原有灯效。
- 蓝牙/2.4G模式下，键盘1分钟无任何操作自动进入省电模式，单击任意按键即可唤醒；通过蓝牙连接时，可在电脑端查看键盘剩余电量。
- 键盘刷写固件补丁需切换至有线模式，刷写完成后请重新插拔USB线并重启键盘左上角的电源开关。
- 键盘回报率：有线模式1000Hz，2.4G模式1000Hz，蓝牙模式125Hz。
- 内置1个5000mAh大容量可循环充电锂电池，配备独立电源开关，环保节能，有效延长续航时间。
- 蓝牙、2.4G及有线模式均支持全键无冲。
- 采用Type-C接口，连接更可靠，性能更稳定，充电速度更快。
- 配合专用驱动可调节5档键盘响应速度，最快可达约2.8ms。
- 配合专用驱动在基础自定义功能之上额外增加3层自定义功能：支持双FN层编辑，实现单键双组合功能；新增TAP层实现一键两用，共计4层自定义功能。
- Sleek and stylish design with 101-key layout, featuring Gasket mount and PCB single-key slotting for a smooth and bouncy typing feel.
- Both keycaps and mechanical switches are hot-swappable, allowing users to freely customize with switches and personalized keycaps from various brands on the market.
- Premium build quality with solid materials and highly responsive keystrokes.
- Equipped with two-stage adjustable feet and a hidden 2.4G wireless receiver storage compartment under the top-left nameplate.
- Switch between 15 RGB lighting effects and off mode via the FN+\| key combination, totaling 16 modes: Wave Flow (default after reset), Shadow Follow, Sine Wave, Spinning Windmill, Rainbow Waterfall, Blossoming Prosperity, Gaming Mode, Off, Static, Breathing, Dreamy Rainbow, Trigger on Press, Rain Walk, Key Ripple, Starry Sky, Endless Stream.
- Music-sync RGB lighting available via dedicated software, with 10 additional dynamic modes to choose from.
- Full key customization and macro programming supported in wired and 2.4G modes via dedicated software, which also allows customization of over 16 million colors.
- User-friendly design with a range of common shortcut functions accessible via the Fn key.
- Toggle the top-right switch to 2.4G mode, with the cyan light under the `~ key flashing slowly. Then press and hold FN+`~ for 3 seconds until the cyan light flashes rapidly to enter pairing mode. Insert the receiver at this point to complete pairing. The cyan light under the `~ key will stay solid for 2 seconds when 2.4G connection is successful. Note: Enter pairing mode before inserting the receiver for 2.4G connection. The keyboard is pre-paired at the factory.
- Toggle the top-right switch to Bluetooth mode (BLE5.0/BLE3.0, device names: K98 5.0/K98 3.0). The keyboard broadcasts randomly based on the terminal device’s Bluetooth version and supports connection to up to 3 devices: FN+1=Bluetooth Channel 1 (blue indicator under the key: rapid flash for broadcasting, slow flash for reconnection, solid for 2 seconds when connected); FN+2=Bluetooth Channel 2 (same indicator behavior); FN+3=Bluetooth Channel 3 (same indicator behavior).
- Toggle the top-right switch to the middle position for wired mode, with the white light under the 4 key illuminating for 2 seconds.
- 3-position mode switch on the top right: Left=Bluetooth mode, Middle=Wired mode, Right=2.4G wireless mode.
- Press and hold Fn+Space for 3 seconds to restore factory default settings. Previously paired Bluetooth devices will remain saved.
- Fn+↑=Increase backlight brightness; Fn+↓=Decrease backlight brightness; Fn+←=Decrease backlight speed; Fn+→=Increase backlight speed.
- FN+Q=Switch to Android mode; FN+W=Switch to Windows mode; FN+E=Switch to Mac mode.
- Independent CAPS lock indicator on the left side, and independent Num Lock indicator above the NUM key.
- Fn+Tab=Switch lighting effect colors.
- Fn+Left Win=Lock/unlock the left Windows key (Win lock indicator stays solid when locked, only applicable in Windows system).
- The left Win and left Alt keys swap positions automatically when switched to Mac/IOS mode (Win lock function is disabled in this mode).
- Equipped with RGB ambient light bar: ①FN+Left Shift=Switch Logo light bar modes (5 lights on top right): Stream, Neon, Static (default red), Breathing (default red), Off; ②FN+Left Ctrl=Adjust light effect speed (3 levels, default level 2); ③FN+Z=Switch colors in breathing and static modes: Red, Green, Blue, Orange, Purple, Cyan, White; ④FN+B=Enter battery mode, including battery level and charging status display. The RGB light bar shows battery level via FN+B, with marquee effect during charging, solid green when fully charged, and solid red when low battery. Exit battery mode and resume normal lighting after reset or power cycle. USB connection takes priority for charging indication.
- Side lighting effects available: ①FN+Right Shift=Switch 5 side lighting modes: Stream, Neon, Static (default red), Breathing (default red), Off; ②FN+.>=Adjust side light speed (3 levels, default level 2, cycle increment); ③FN+Right Ctrl=Adjust side light brightness (5 levels: Off, 25%, 50%, 75%, 100%, default 50%, cycle increment); ④FN+/?=Switch colors in breathing and static modes: Red, Green, Blue, Orange, Purple, Cyan, White.
- Press and hold the FN key to display current status: indicators under the 3 mode keys, 3 Bluetooth channel keys and 3 system keys all illuminate white. Release FN to resume normal lighting effects.
- Auto power-saving mode activates after 1 minute of inactivity in Bluetooth/2.4G mode; wake up the keyboard with a single keystroke. Battery level can be displayed on your computer when connected via Bluetooth.
- Firmware update requires wired mode. After update, please re-plug the USB cable and toggle the power switch on the top left corner off and on.
- Keyboard polling rate: 1000Hz (Wired mode), 1000Hz (2.4G mode), 125Hz (Bluetooth mode).
- Built-in 1x 5000mAh high-capacity rechargeable lithium-ion battery with integrated power switch for energy saving and extended battery life.
- Full N-key rollover (NKRO) supported in Bluetooth, 2.4G and wired modes.
- Equipped with Type-C interface for more reliable connection, stable performance and faster charging.
- 5-level adjustable keyboard response speed via dedicated software, with a minimum response time of approximately 2.8ms.
- Dedicated software adds 3 extra layers of customization on top of basic functions: supports dual FN layer editing for single-key dual-combination functions; adds TAP layer for one-key dual-purpose functionality, totaling 4 layers of programmable customization.