Post a picture of the tool so we can tell you where it comes from and you can contact the dealer/manufacturer directly, which most likely isn't Bitmain, most of the Asic fixture tools come from Zuesbtc, so that would be your first shot >
https://www.zeusbtc.com/ASIC-Miner-Repair/Repair-tools/Test-fixture/The other brand is Asic Repair, a Russian-made tool that is more advanced than the Chinese one, so it's more than likely that whatever you have is one of the two I mentioned, so do post an image link using
https://www.talkimg.com/ and I will be able to help you better.