Greatest item you have bought

Prompted by a thread on the polar opposite, I’m curious about things folks have bought that have legitimate made a difference for them (I’d rather exclude clubs but if you feel great about a driver, dump it in here).

For me, the martini tees are a game changer. 2 seasons with one tee… also consistent height (unsure about flight pattern or power tbh).

Also love my Bushnell Phantom 2 GPS