Hi Flame 4 Wheel Heavy Duty Trolley Assembly with Silent M10 Bolt & 3 Nuts for All Standard 1-5/8" or Taller Strut Channel (Pack of 1 Silver): Amazon.com: Industrial & Scientific
Andustrial 3-in Square Strut Bracket in the Strut Accessories department at Lowes.com
Amazon.com: UNISTRUT Genuine P2950-EG 4 Wheel Trolley Assembly for use with P1000, P1001, P5000, P5001, P5500, P5501 and All 1-5/8" or Taller Strut Channel : Industrial & Scientific
2PCS Trolley Assembly Electric Hoist Easy Installation Roller Trolley Silent for use with Unistrut 1-5/8" Wide - AliExpress
Amazon.com: 6 Wheel T Type Unistrut Trolley, Stainless Steel Strut Channel Roller Trolley Applicable to1-5/8" 12 Gauge Metal Strut Channel, Load 1000 Pounds Silent : Industrial & Scientific
Andustrial 3-in Square Strut Bracket in the Strut Accessories department at Lowes.com
NEWHOUSE ELECTRIC 1-5/8 in. Trade Size Heavy-Duty Steel 4-Wheel Trolley Assembly with Sealed Bearings for 1-5/8 in. Strut Channel HT4W-158S - The Home Depot