The diameter of inserts varies between manufacturers. Only the following insert part numbers are compatible with these large opening vials. • 24719, 24720 Glass insert, conical bottom, 6 x 29 mm • 24721 Glass insert with bottom spring, 6 x 29 mm • 24722 Polypropylene insert with bottom spring, 6 x 29 mm • 24717, 24718 Glass insert, conical bottom, 6 x 31 mm • 24715, 24716 Glass insert, flat bottom, 6 x 31 mm closure type black polypropylene hole cap