Metro's new transit passes, tentatively approved yesterday by the board, will look very much like a Farecard because that's what they are.

The passes will be specially marked $5 Farecards, but will lose all their value if not used within two weeks.

Each card will contain $5 in subway rides and unlimited one-zone bus rides. At subway stations, passes will be inserted in the Farecard enter and exit gates just as normal Farecards are used. To board a bus, the rider need only flash the Transit Pass/Farecard. Colors will be changed every two weeks so bus drivers can easily spot used-up passes.

There will be three passes:

The $10 pass, available to everybody, provides unlimited bus rides within one zone, or the entire District of Columbia. It will make it possible for a commuter to ride the bus, the train, then the bus again on the same trip without paying two fares.

The $16 Maryland-D.C. pass also provides $5 worth of subway rides and unlimited bus trips across any number of bus zones. It will be useful for people who take the bus into Washinton, then transfer to the subway. It also will be good for bus trips anywhere in Maryland.

The $16 Virginia two-zone pass also provides a $5 worth of subway rides. However, it permits only limited bus trips-across two zones lines in Virginia. If used to cross more zones, extra fare must be paid.

The transit pass will be sold at Metro's ticket and token outlets and will be available several days in advance of each two-week period.

Metro is studying the possibility of vending transit passes with machines at Metro stations, but that is not possible at the moment, according to Tom Brinton of Metro's marketing office.