a permanent stressed end cap for a post tensioned concrete member includes a grout retention feature adapted to retain a filler material within a void formed by a pocket former . the grout retention feature may be a generally knob or mushroom shaped , hex - headed , or square body extending from the cap . the grout retention feature may include one or more protrusions extending from the exterior of the cap . the grout retention feature may include one or more surface textures on the exterior of the cap .