Item Details: -Sliding blocks with spring with thread m8 for 8mm slot or 10mm slot -30/40 M8 is suitable for aluminum profiles with a groove width of 8mm in the 30/40 series -40 M8 is suitable for aluminum profiles with groove width of 8mm such as 4040 4080 8080 -45 M8 is suitable for 4545 4590 9090 and other aluminum profiles with a groove width of 10mm Specification: Size:as shown Material: carbon steel Color:Silver Package Contents: 20* Shrapnel Nuts M8 Notes: The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.