The Snap Vial is made of USP Type 1, Class A, 33 Borosilicate Glass or USP Type 1, Class B, 51 Borosilicate Glass. The Snap Top PP Cap uses high-quality PP material, which is easy to operate and can be heard when pressed down. With a click, the seal is in place. Aijiren's Snap Vial has two horizontal lines on the bottle mouth.