It weighs 250gm and is designed for alloy or glass platters. I don't use it any other mats. Flicking the SL1210 platter without the acrylic mat or with a felt mat definitely makes it ring, but flicking with the acrylic mat on gives a dull thudding sound without any hint of ringing at all - my test material consisting of my nails & ears right close to the platter lol.