It's a bottle cap that removes bottle caps. Prints with no supports. Add to 10mm x 3mm magnets to stick it to the fridge. This design requires a bottle opener insert kit which is available at Amazon. 

The openers I made are printed in white PLA, sprayed with body filler primer and then spray painted with the final color…but you could skip the painting. 

They work great. They are the perfect size for an adult hand and the cap just seems to fall into your fingers.