The Kaiko wrist spikey is discreet to wear and is primarily used as a harm minimisation tool that provides 'hurt without harm'.  Also available in black and purple. 
We have had customers who’ve bought the wrist spikey fidget from us and told us it has been the best tool to help them warding against tendency to self-harm, as it provides 'ouch' without damaging the skin. Of course, the spikey fidget does not replace accessing professional help. It is a useful tool for the kit-bag.