Better Built window weatherstrip

My wife & I recently purchased a home built in 1999 with Better Built single hung tilt windows. The rubber seals/weatherstripping on most of the windows is hard/brittle and not making a good seal.

The weatherstipping slides into a T-slot and looks like the T portion is 3/16" wide and the round bulb is 5/16". The weatherstipping is black.

Can someone help find replacement weathersripping?

Thanks,
John.