Thanks for your message. We are so glad to hear that you have received the heatbed. and the screw thread is M3. Hope you will like it. Have a nice day. hi, friend, Thanks for your message. We are so glad to hear that you have received the heatbed. and the screw thread is M3. Hope you will like it. Have a nice day. Your previous message I received MK2B heatbed 120mm x 120mm. Thankyou. Please help identify screw thread size?