A shaving razor blade unit including a housing having a primary guard at a front of the housing and a primary cap at an upper surface at a back of the housing, one or more primary shaving blades between the primary guard and the primary cap, a rear wall having a rear exterior surface extending downward from the upper surface at the back of the housing to a terminating surface, and a trimming blade mounted on the rear wall and having a trimming cutting edge extending at least partially beyond the terminating surface inside of an imaginary extension of the rear exterior surface, the rear exterior surface defining a secondary cap for the trimming blade. The back of the housing includes a trimming guard including spaced guard segments.