Our F-Series metal snap domes (tactile snap domes) are four-legged switch contacts that were designed specifically for mounting on single or double sided printed circuit boards, flex circuits and membranes, where traces can be fed under the domes on the same side of the board. They come in eight different sizes, and can be used for contact or tactile element only. 
The size of F series snap dome is from 5mm to 20mm in a range of (trip) force, typical 125- 500 g. The trip force, rebound/return force, click, travel, and height, etc., can be adjustable according to clients' request.