YSI 550A D/O meter measures dissolved oxygen in mg/L, percent saturation
and temperature at depths up to 100 feet. It features a waterproof IP-67
rated, impact-resistant case and field-replaceable D/O electrode module.
The 550A has a bright backlit display, automatic push-button calibration,
low-battery indicator, as well as automatic temperature (ATC), salinity,
and manual altitude compensation. Other features include easy-to-replace
screw-on cap membranes, over 2000 hours battery life, calibration in
either mg/L or % saturation, and a built-in storage chamber to protect
the probe when not in use. The weighted probe sinks easily and is available
with four cable lengths, 12, 25, 50 or 100 feet. The meter is supplied
with 4 C cell alkaline batteries & replacement D/O membrane kit.