I have been doing HVAC work, repairing residential plumbing and installing systems for about 4-5 years. We have always used a set of Malco sewing machines with black handles. Our angled pair of jaws broke after about 10 years of heavy use. The contoured buttons on them feel a lot better than the straight black buttons on a pair of Malcos that I'm used to. The "thumb lock" is also an improvement on the older side locks commonly found on sheet metal tools.