Nylon Housing with brass wheels

Application: Horizontal Sliding Window
Housing Face Length: 1-1/2 inch
Housing Face Width: 1/2 inch
Housing Width: 3/8 inch
Housing Length: 1-3/8 inch
Housing Material: Plastic
Roller Type: Flat
Roller Width: 3/16
Roller Diameter: 1/2"
Roller Material: Brass
Working Height: 3/16 inch 0.188

NOTE:
V1183 = Nylon Wheel, V1187 = Brass Wheel V1178 = Brass Wheel - - 1178 / 1183 / 1187 all share the same housing.
The difference between 1178 and 1187 is working height ( 0.188" vs 0.240").