Genuine Unistrut P2749-EG 2 Wheel Light Duty Trolley Assembly for use with P1000, P1001, P5000, P5001, P5500, P5501 and All 1-5/8 TROLLEY ASSEMBLY - 2 wheel light duty trolley assembly. FOR USE WITH - P1000, P1001, P5000, P5001, P5500, P5501 and all 1-5/8. CLEVIS MATERIAL - 12 gauge, wheel bearings are stainless steel. SILVER FINISH - Electro-galvanized; ASTM B633, Type III. DIMENSIONS - 1.6 x 1.5 x 1.2 inches.