F/S Lefthand Desantis Slant Shoulder Holster with Single Ammo Pouche this holster will fit the following revolvers with 4 inch barrels.
S&W models 10, 12, 13, 15, 19, 65, 66, & 67.
Ruger : Securty Six, Speed Six and Service Six
Colt : police Positive and Diamondback.
and come with a free attached ammo pouche for extra ammo.
I cannot find this holster on the current Desantis website , but Desantis's current list prices for similar shoulder holsters runs between $78 and $160 .
A picture is below, Asking $ 45 plus shipping and insurance.