Helps drivers improve the accuracy of logbook calculations, reducing the chance of excess hours on duty, violations and fines. Reflects current HOS Rule for property carrying drivers. Hours of service ruler runs along top edge for easier use. Tire-tread depth gauge printed on back side. Made of durable, flexible, yellow plastic. Measures 2" x 7-1/4". For use on 5-1/2" x 8-1/2" or 8-1/4" x 8-1/2" log books, KellerScan logs and all small log summary envelopes.