I have a Timex Ironman from around 1998 or so. It has been caught on many a mechanism, endured lots of impacts in industrial settings, been dropped 20 feet while using it as a stopwatch on a catwalk. It's been chemically attacked over the years by MEK, MIBK, pure sodium hydroxide, semi-dilute sulphuric acid, and a little bit of hydrochloric acid to the point where the plastic buttons melted and bezel is gone, and one button has been completely destroyed. It has not been subjected to all that much heat, maybe 300 degrees at the most. Functionally it works like new, even though the buttons generally have to be activated with pick-type tools. It's still waterproof. I wear it for yard work and home projects.