By Castin' Craft. 6 count 1 3/8" (35 mm) x 1/2" deep, holds 1/2 oz each. Tray is made of durable, smooth, re-usable polypropylene. Mold release is recommended for longer mold life. Instructions & tips sheet included with a link to pdf resin jewelry, knobs, & project books. Photos are sample designs. Made in USA.