RainWalker
RainWalker OÜ - an independent Estonian manufacturer of compact pentest hardware based in Tallinn. The Kiisu line is a card-sized alternative to Flipper Zero, compatible with Flipper Zero firmware. SAPSAN is launching Polish distribution of the RainWalker brand.
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KIISU V4BR - Flipper Zero Alternative
RainWalkerOriginal price 409.00 zł - Original price 409.00 złOriginal price409.00 zł409.00 zł - 409.00 złCurrent price 409.00 złIn stockKiisu V4BR. Flipper Zero, in your wallet. Specifications → Everything the Flipper Zero can do. In a card for...
View full detailsOriginal price 409.00 zł - Original price 409.00 złOriginal price409.00 zł409.00 zł - 409.00 złCurrent price 409.00 zł
Who is RainWalker
An Estonian team from Tallinn (OÜ reg. 16704677), creator and owner of the Kiisu project - a family of multifunctional development boards in a credit-card form factor, fully compatible with Flipper Zero firmware. Hardware designed and manufactured in the EU, short logistics chains, full CE/RoHS compliance.
The Kiisu product line
Kiisu V4BR - the flagship card-sized board with a full pentest stack: SubGHz CC1101 (with optional external antenna), NFC ST25R3916, RFID r/w/emulator, IR rx/tx, Bluetooth Low Energy, iButton, GPIO Flipper-compatible. Dual-MCU: STM32WB55 (80 MHz main) + STM32G431 (170 MHz aux), more compute power than the reference Flipper. On-board sensors (accelerometer, compass, temp, light), with optional BME680 (VOC) and VL53xxx (ranger) for user installation.
Kiisu SMOL - a smaller modular evolution of Kiisu, available as keychain or watch (pre-assembled). Main board: STM32WB55 Cortex-M4, CC1101 SubGHz (300-348/387-464/779-928 MHz), ST25R3916 NFC, RFID EM4100, IR, BLE, OLED SSD1306, 512 MB SD on-board. The modular ecosystem adds dedicated boards: Dual-Band WiFi (ESP32-C5) with GPS, LoRa with Meshtastic, dedicated NFC/RFID + LIR2032. Currently on Indiegogo.
What sets Kiisu apart as a Flipper Zero alternative
- Card format / modular keychain / watch - discreet, fits in your wallet or on your keys
- Flipper Zero firmware compatibility - the entire community and forks (Momentum, Unleashed, RogueMaster) work from the first flash
- RF stack broader than Flipper: SubGHz, NFC, RFID, IR, BLE, iButton in V4BR; additionally LoRa/Meshtastic, GPS, Dual-Band WiFi in SMOL
- GPIO pin-compatible with Flipper Zero - Flipper shields and accessories work without modifications
- Dual-MCU in V4BR - more compute power for complex workflows
- EU origin - designed and manufactured in Estonia, CE/RoHS
Professional applications
Red team field ops, NFC/RFID/iButton research, SubGHz audits (smart locks, IoT 433/868 MHz), IR audits (smart home, AV), BLE sniffing and emulation, Meshtastic mesh networking (SMOL+LoRa), IoT prototyping with sensors.