Fun little hello kitty clicker, It is 37mm x 27mm.

I used a standard MX style keyboard switch.  

[https://www.amazon.ca/dp/B0CBPV5FLB?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1](https://www.amazon.ca/dp/B0CBPV5FLB?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1)

I recommend inserting the switch into the base first and press firmly (make sure it is the right way), and then the top can be easily aligned for pressing into place on the switch stem.