Marlin is the hand winding water resistant series of TIMEX regular sized mechanical men's watches. In the early 60's the M22 movements were used. In the late 60's through late 70's the M24, M25 (date), M27 (day-date) and M105 (date) were used. 

You can recognize a TIMEX Marlin by the printed waterproof or water resistant on the dial. Notice that other TIMEX models also can have water resistant on the dial. Case size and other things printed on the dial determine what TIMEX series it concerns.

TIMEX Marlin waterproof ref. 26061 from 1972

Timex US Catalog 1977

Waterproof vs water resistant and 25 Metres

When did waterproof change into water resistant and what is there to know about the watches with 25 metres on the dial? You can read all about it here.

TIMEX Marlin Calendar date window

The date versions of TIMEX watches are called Calendar and the watches that also indicate the day are called Day-Date. Untill 1977, TIMEX used square date windows for their Marlin Calendar series. Starting in 1978, they switched to the trapezoid date window which we already knew from the TIMEX Electric watches. 

A rare TIMEX Marlin Calendar Racing 

A formal goldtone square case and bracelet combined with the sporty look of the dial due to this black and white racing striping ring. I absolutely love it! A perfect example of extravaganza from the early 70's. In NOS condition from Italy. Reference 27560.

TIMEX Marlin Sports Calendar