Comparison : Item # B4763-01B, 303 Stainless Steel Gasketed Window Sight, Without Reflector, 5/8" Hex, 1/4” NPT
Item # B4763-02B, 303 Stainless Steel Gasketed Window Sight, Without Reflector, 3/4" Hex, 3/8” NPT
Item # B4763-03B, 303 Stainless Steel Gasketed Window Sight, Without Reflector, 15/16" Hex, 1/2” NPT
Item # B4763-04B, 303 Stainless Steel Gasketed Window Sight, Without Reflector, 1 1/16" Hex, 3/4” NPT
Item # B4763-05B, 303 Stainless Steel Gasketed Window Sight, Without Reflector, 1 3/8" Hex, 1” NPT