This staining dish can hold up to 4 cover slips measuring 17-23 mm wide, and up to 30 mm long. Longer cover slips can be accommodated if the cap is removed. The jar comes with a white polypropylene screw cap with a PTFE coated polyethylene liner. It is manufactured from soda-lime glass and is resistant to most chemicals. In addition to staining applications, the Columbia jar can be used for cleaning cover slips, as well as coating them with materials such as polylysine or silane.