3mm x .5mm x 8mm long for the backplate, 3mm x .5mm x 12mm long for the head. Replace 'em all. A screw set for a Magnum XL/XLS .25>.53 is perfect, but any hobby shop will probably have these in the DuBro stuff, probably in the R\C car section. A good fastener store will have them by the box (100) for about $4...I bought boxes, FWIW.

Steve
Steve Helmick
Renton, Washington
USA