Uwatec bottom timer, wrist mounted, about $225. Sealed lifetime battery, last for years, gives plenty of warning when time to replace (first one went 2 years/ 100 hrs in waning mode without losing any dive date).
Only drawback, are no clock (pure timer), not lighted or downloadable, all non-issues for me.
Requires paying attention to your dive and knowledge of tables, but works well for multi-level, multi-dive, multi-gas, basically as well as the ultimate dive computer located between your ears.
On my second, have used exclusivly since 2000, hundreds of hours underwater.
Curtis