Flat head clear acrylic plastic standoffs with a screw in head. 

Finish - Clear Acrylic

Dimensions
A - Diameter of head: 19mm
B - Depth of body: 25mm
C - Diameter hole to be drilled in sign for fixing: 10mm
D - Maximum panel thickness: 12mm

Available as single units, box of 60 or box of 300. 

Also available in other sizes:

clear acrylic standoff 13mm x 13mm (7237415)

clear acrylic standoff 13mm x 19mm (7237515)

clear acrylic standoff 19mm x 19mm (7237715)