The Etlin Daniels FLT8T5-PH is a non-shunted, short-type, plunger-end lampholder (socket) designed to convert existing T8 or T12 linear fluorescent fixtures to T5 lamps. It enables retrofitting by accommodating the smaller G5 base of T5 lamps, often used in combination with a fixed-end socket LH0868 (FLT8T5-FH) to handle lamp length tolerances.
Link to T5 lamps that this support fits