Hercules Universal Heavy Duty Adjustable Metal Bed Frame with Double Rail Center Support Bar Fits All Mattress Sizes Review ChangeNightElf August 27, 2018 November 13, 2018 No Comments on Hercules Universal Heavy Duty Adjustable Metal Bed Frame with Double Rail Center Support Bar Fits All Mattress Sizes Review The Hercules Universal Heavy-Duty Adjustable Metal Bed Frame fits all size mattress sets. This solid black matte powder-coated steel bed frame is engineered to support heavier mattress sets and feature adjustable sliding end rails.