Tomsenn T-SP328 Surface Pro 4 Bluetooth keyboard: 

Tomsenn T-SP328 Bluetooth keyboard is specially made for Surface Pro 4 Type Cover and perfectly complements its thin, lightweight design style 
Designed to get work done 
Enhanced with magnetic stability to keep the keyboard steady, you can work just as comfortably on your lap as at your desk. 
Auto-Sleep Mode 
When it does not get any manipulating instruction in 15 minutes, the power indicator light of the keyboard will be off. But it can work again after you press any button. 
Package included: 
One Surface Pro 4 Keyboard 
One Charging Cable 
One User Manual