Manufactured from chemically inert, borosilicate glass, these flat bottom, HPLC reservoirs include a UV-inhibiting, plastic safety coating which blocks virtually all UV up to 385nm; so your light-sensitive reagents are protected. The safety coating will also help control a spill should a break occur. The top thread is GL-45 for connection to various HPLC mobile phase cap systems. Permanent graduations and marking spot are included.