Specification Brand : YVSPTIK BulletPoint1 : 4040 M6 T Slot Nuts for 4040 aluminum extrusion with 8mm slot, use for T-slot aluminum profile 4040 series. BulletPoint2 : Spring ball loaded makes these T slot nuts sit and stay where you want them,and don't slide around while your trying to screw into them.It was so much easier than fiddling with the stock T nuts that refuse to lock in place correctly.You can insert and remove these T slot nuts easily. BulletPoint3 : If you work with T slot extrusions,these are a must have.These T slot nuts fits perfect on 4040 extrusion or 4040 rail with lots of different components on your rail.For you to mount something else. BulletPoint4 : If you also lost pieces to your printer and need replacement, they fit nice and secure in rails.Use them to add new brackets to stiffen the frame on your 3D printer (Tevo Tarantula). BulletPoint5 : Carbon steel :All high quality carbon steel construction,high hardness.Nickel-plated surface, rust resistance.4040 Series Aluminum Profile T-Nuts widely Use to build CNC routers, 3D printers, CNC laser cutters, CNC plasma cutters, robotics projects, 3D carvers, machine guards, workstations,and more. Color : M6 DriveSystem : Slotted DriveSystem1 : Slotted DriveSystem2 : External Hex ExteriorFinish : Aluminum,Carbon Steel ExternallyAssignedProductIdentifier : 8436580310888 ExternallyAssignedProductIdentifier1 : 795890845304 ExternallyAssignedProductIdentifier2 : 0795890845304 FinishType : silver GpsrSafetyAttestation : 1 GradeRating : commercial ItemName : YVSPTIK 4040 Series M6 T Slot Nuts Roll-in Spring Ball Loaded Elastic Nuts 20 Pack Carbon Steel for 4040 Series Aluminum Extrusion Profile Rail with 8 mm Slot for 3D Printer ItemPackageDimensions_Height : 10.3886 centimeters ItemPackageDimensions_Length : 2.2098 centimeters ItemPackageDimensions_Width : 6.7056 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : t-nuts Manufacturer : YVSPTIK Material : Carbon Steel Material1 : Aluminum Material2 : Steel Material3 : Aluminum MeasurementSystem : Inch MeasurementSystem1 : Metric MeasurementSystem2 : Inch MetalType : Carbon Steel MetalType1 : Aluminum MetalType2 : Nickel MetalType3 : Carbon Steel ModelNumber : a18103100ux0446 NumberOfItems : 25 NumberOfPieces : 15 PartNumber : a18103100ux0446 ProductDescription : Specification: Color:Silver Material: Carbon Steel Thread Type: M6 Size:21.5 x 13.3 x 7.4 mm/0.85 x 0.52 x 0.29""(L x W x H) Feature: 1.It can be directly into the aluminum slot hole in any of the assembly point 2.Back spring ball can be fixed its position which make installation very simple and reliable 3.Profile connection is one of the most use of accessories 4.Made of Carbon Steel and lasting performance Note: Since the measurement tools are different, there will be 1-3 mm error, not to be a basis/reason for return. Package include: 40x M6 Thread T Spring Nut