In short, it depends on the federation and their rules. Powerlifting Australia goes by World Powerlifting Federation rules, which state: "4.8 BELT To be allowed for use in a Powerlifting Competition, a Belt – (i) can only be worn on the outside of the lifter’s Suit and between the lifter’s ribcage and hips (ii) shall be a single band of leather, of maximum width 10cm and maximum thickness 13mm (iii) may not have any padding or supports attached to or within any part of the Belt (iv) shall have a lever or pronged buckle attached by studs or stitching to one end of the band of leather, so as to affix the belt closed around the lifter’s ribcage to hip area (v) shall, if a belt with a pronged buckle, have one loop around the band of leather so as to affix any part of the band of leather which protrudes past the buckle onto the Belt; no more than 20cm of the band of leather may extend past that loop (vi) must be either plain i.e. of a single colour with no logo or emblems, or patterned i.e. covered in total or part with a pattern but with no logos or emblems and may bear the lifter’s name and/or the logo or emblem of the lifter’s nation and /or the logo or emblem of commercial entities approved by the World Powerlifting Board and/or logos or emblems of the manufacturer of the Belt, all save as to Rule 4.12." We recommend checking with an approved meet coach/representative prior to competing, or checking the rulebook before designing your belt to ensure it meets your Federation requirements.