Our product
Collar: 
Set collar, solid collar bore:  1/8" to 6"    3 mm to 160 mm
1 pc collar, single split collar bore:   1/8" to 6"   3 mm to 100 mm
2 pc collar, double split collar bore:  1/8" to 6"   3 mm to 100 mm
Thread collar bore:  10-32 to 2-12    M4 to M30
Hinge collar bore:  3/8" to 2"   9 mm to 50 mm
Coupling:
Set screw rigid coupling  1/8" to 4"   3mm to 100 mm
1 pc shaft coupling, single split shaft coupling, rigid coupling 1/8" to 4"   5mm to 100 mm
2 pc shaft coupling, double split shaft coupling, rigid coupling 1/8" to 4"   5mm to 100 mm

Material:
Steel / stainless steel 304 / aluminum According to customers' requirements
Finish:
Black oxide or Zinc Plating finishing for stell Bright finishing for SS304 and aluminum Customized finishing