Wheaton® dropper tip screw caps are designed for 13mm dropper tips and Wheaton 6mL 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: 13-425 GPI (13mm).