Mechanical counter. It can work on most AC/DC 6-90V equipment System timing, including: total accumulation hours tot, max hours: 99999.9h, resolution 0.1 hour. Unique design including: easy installation, snap-in installation, save time and effort, tool free 6 digit display, easy to read 7mm digits external of energy, long life of 10 years. Product Description RL-HM009 Snap IN Mechanica Hour Meter for DC Equipment 8-80V powered such as forklifts, golf carts, floor care equipment and other battery powered equipment. Product function: System of Timing: Total Running Hours Accumulation TOT Max Hours: 99999.9H, Resolution 0.1 Hour Unique Design: < p > Easy installation, long service life 2-year warranty Product specifications: Display: 999999V with working indicator (Automatically recycle to zero) Digit Height: 7MM Working voltage: 6-80V AC 50/60hz (This meter is DC 6-80V If you need AC 110-220V, please please kindly leave message to us &gt; Resolution: 0.1hours Storage and operation: -40C to +85C temperature Humidity: 95% RH + 32C for 2 hours Protected From: Aiternator load dump, inductive Switching Polarity: Positive / Negative Case Style: Front Panel Mount, Other styles are available SZRH A-B