Promountings.com I Beam Roller Mounting for Heavy Bag: 4.5" to 7" Wide I-Beam CHECK OUT THE VIDEO AT THIS LINK http://www.youtube.com/watch?v=rMzrlXuHPcg For I-Beams that are between 4.5" up to 7" Wide For Heavy Bags up to 250lbs Fabricated from 3/16" steel plate and powder coated for a durable lasting finish. Ships Assembled, Made in the USA!