These lightweight High Strength Aluminum Attachments were developed in 2003 and are 66% lighter than steel attachments but have a higher tensile strength. They incorporate a Urethane coated handle that is so durable we have never had a single replacement request in 17 years. Additionally, they have composite bushings at rotational points and tamper-proof features built into every attachment. One important extra benefit found in these lightweight attachments is that they can be used on adjustable pulley systems. Heavier steel attachments can fall unexpectedly when the weight stack pin is pulled, striking the user. Another industry first from American Barbell.