Microdermal Top. Titanium Gem Disc Top for microdermal piercing (dermal anchor). 0.8mm internally threaded. 3mm or 4mm gem disc top. Available in a choice of gem colours. Made from high quality surgical Titanium. 0.8mm internally threaded Gem Disc, fits 1.2mm internally threaded microdermal post. For help and information please read our sizing guide and body jewellery guide, . For use in the healed piercing. Top (does not include base) for a microdermal piercing, attach the top to the piercing by screwing into the base of the microdermal.