Strain relief for UMO feeder stops the filament from being bent too tightly as it enters the feeder.The bracket attaches through existing screw holes in the feeder. A piece of 0.25" bowden tube (same as stock tube) slots into the bottom of the bracket and controls the bend of the filament as it enters the feeder. I used a piece long enough to go from my filament storage box to the feeder (about 60 cm).A slot allows the bracket to be slipped on without removing the filament.