MHT Technologies > MHT Lighting > Support If you are having an issue with any MHT Lighting fixtures, please use the forms below for RMA and Warranty claims. If you are not sure what to do, you may contact us through the form to the right. 718.524.4370 Do you need to Register for Our Product Warranty? Please fill out this form. Do you need to Return Materials or file a Warranty Claim? Start the process with this form.