Blood Cell Counting Vial with Attached Snap Cap, Graduated to 20mL, 250/Bag, 4 Bags/Unit-107047 Globe Scientific's polystyrene (PS) cell counter cups come with a polyethylene (PE) snap on lid. The cups are graduated at the 10mL and 20mL marks. Size(L x W x H): 21.5 x 14.25 x 18