Wheaton® dropper tip screw caps are designed for 20mm dropper tips and Wheaton 30, 60 and 125mL plastic dropping bottles. Manufactured from radiation grade polypropylene. Caps are available in multiple colors which facilitates rapid identification of individual samples and allows for coding of multiple product lines. Fully autoclavable for sterile applications. Material: Low-Density Polyethylene. Thread Finish: 20-410 GPI (20mm).