1) Head diameter is 18mm or just short of 3/4 of an inch diameter including the back piece. 2) Image size is just slightly over 1/2 inch in diameter. 3) ALL auto sized fasteners are $12.00 per set! (customized or not), open back mounting sizes are $15.00 a set
I also offer:
a bracket for $8.00. The bracket works for vehicles that do not have the plastic screw inserts to change out behind ones plate. Also for anyone that wishes to use 4 Fasteners and their vehicle only has 2 holes.
Different sizing to accommodate with a frame & without.