Power-Strut® Top Grip™ PS-TG-1/2-EG Clamping Nut With Short Spring, 1/2-13 Thread, 3/8 in THK, For Use With 1-5/8 in W Channel, PS 100, PS 150, PS 200, PS 210,PS 300, PS 400, PS 500, PS 520, PS 560 Channel, Sintered Metal