Specification Brand : Yanmis BulletPoint1 : ✔【Excellent Material】- These pulleys are made of high quality metal and plastic material, sturdy and wearable. BulletPoint2 : ✔【High Performance】- Internal lubrication grease, smooth , good effect. U-shape design, smooth reduces friction. BulletPoint3 : ✔【Ideal Replacement】- The pulley wheel widely used in doors and windows to track and drive mechanical equipment. BulletPoint4 : ✔【Slide Flexible】- There are total 4 pieces of pulleys in one set that you many use for many projects. BulletPoint5 : ✔【Overall Size】- Inner Diameter: 8mm/0.3in; Outer Diameter: 39.5mm/1.6in; Thickness: 20.1mm/0.8in. Color : silver tone ExternallyAssignedProductIdentifier : 4894878095260 ExternallyAssignedProductIdentifier1 : 0715990523636 ExternallyAssignedProductIdentifier2 : 715990523636 GpsrSafetyAttestation : 1 IncludedComponents : Deep Groove Ball bearing ItemName : Pulley Rail Ball Wheel, 4Pcs 0840UU 8x40x20.7mmU- Pulley Roller Wheel for Doors and Windows Control Mechanical Devices ItemPackageDimensions_Height : 12 centimeters ItemPackageDimensions_Length : 4 centimeters ItemPackageDimensions_Width : 8.5 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : deep-groove-ball-bearings Manufacturer : Yanmis Material : Metal ModelNumber : Yanmiskwgvc5qhfe NumberOfItems : 1 PackageLevel : unit PartNumber : Yanmiskwgvc5qhfe ProductDescription : Description: Made of high quality material, these wheels are , sturdy and . There is grease, it is quiet running, good effect. U-shape design, smooth can reduce the friction. There are a total of 4 roles in a set that you use for many projects. It uses wide in doors and windows to track and control mechanical devices.