The Oceanic F10 was designed by freedivers for freedivers. This fantastic training computer features: Endorsed by F.I.I. The Leading Freediving Education Agency Freedive Mode Main displays Depth and Elapsed Dive Time with access to either a pre-set countdown timer or lap timer User defined surface recovery time Repeating elapsed dive time alarm Repeating depth interval alarm and 3 max depth alarms - with flashing LED and auto-backlight illumination 99 dive log with Max Depth, EDT, Surface Interval :01 step profile scroll - EDIT and Depth History Mode including total EDT and number of dives Max depth ever with its EDT Longest EDT ever with its Max Depth Average Max Depth EDT, and number of dives per day Digital watch functions including alternate time zone, chronograph, daily alarm, and countdown timer User-Replaceable Battery Optional PC Downloadable with 1 second sampling rate Martin Stepanek, Multiple World Record Holder and F.I.I. Founder says it best. ...It has many freediving specific features including a wide variety of convenient alarms. It's ideally suited for all types of breath-hold diving, spearfishing or freediving, recreational to competitive. I've personally been diving with this computer for the past 14 months and find the repetitive depth alarm to be of specific value as it can track each atmosphere. The F.10 also features a surface interval alarm which is very beneficial during my interval training for competitive freediving. It has a unique safety feature of an on-going stopwatch so whilst in-water my running time does not get erased if the computer becomes submerged- unlike with any other freediving computer. Right now, this is simply the best freediving computer on the market- period." "