PCB Holder 4cm x 6cm

I created some amplifier circuits for my virtual pinball project: http://lilmikey.com/2017/02/16/virtual-pinball-cabinet/

I build them on small, cheap uxcell 4x6cm perf boards: https://www.amazon.com/gp/product/B0166GCD42/ref=oh_aui_detailpage_o07_s01?ie=UTF8&psc=1 and needed a decent way to mount them to the cabinet. The perf boards snap in and hold snugly and can be secured by 4 screws. The images are of an earlier 2-screw version.