The reinforced top and tooled lower end of this Kimax® column provide extra strength and a tight, leakproof fit with an all-PTFE stopcock. An o-ring under the PTFE fitment maintains a liquid-tight seal over a large temperature range (0-100°C). Liquid contacts only glass and PTFE. The stopcock is easily removed, providing easy access to column packing. The 17810 series has a 250mL reservoir at the top of the column.