The RM4UMTGFL is a replacement pair of front rack ears for 4U RM series rack-mount aluminum instrument enclosures. Hammond describes it as "hardware - rack-mounting flange for RM series, 4U", and it is listed in the RM ordering table under Replacement Front (Pair) of Rack Ears for the 4U height. Integrators and maintenance staff use it to replace bent or lost ears, or to convert a 4U RM enclosure that has been used on a desktop back to 19 in rack mounting.

The part page lists the material as aluminum and the colour as black, and the part is classed as a mounting flange accessory. The drawing shows each flange with a front-view height of 177.04 mm [6.970 in], a side-view width of 30.48 mm [1.200 in] and a thickness of 3.18 mm [0.125 in]. Rack attachment is through 2X 0.422 x 0.250 slots, and the flange fixes to the enclosure through 2X Ø3.99 mm [Ø0.157 in] holes with countersinks called out as 2X Ø0.20 in x 0.31 in, Ø0.39 in x 82.0°.

The RM ordering table notes that the replacement rack ears include enclosure mounting screws. In the RM series, 19 in mounting versions (the full 16.60 in wide enclosures) ship with one pair of rack mounting flanges, so the RM4UMTGFL is the matching spare for 4U full-width models such as the RM4U1908, RM4U1913, RM4U1918, RM4U1922 and RM4U1928 solid and vented enclosures.

The RM4UMTGFL is RoHS and REACH compliant, ships in a box at 0.4 lbs (0.18 kg), and carries UPC 623980505862 and UNSPSC 43201602.