Rockers — the mid-70s reggae drum feel (Sly Dunbar, the Revolutionaries) that puts the kick on **all four beats** under the same cross-stick on 3. Where the one drop empties beat 1, rockers fills it, so the groove is heavier and more militant while the guitar skank (2 and 4) and the organ bubble ("an-a" of each beat) stay exactly where they were. The bass gets busier too: root on 1, a push on the "and" of 2, a run up through the 3rd and 5th at the end of the bar.
Listen for the kick as a four-on-the-floor pulse that never swings or syncopates — the syncopation is all in the hands. Mute the bass to hear how plain the kit is on its own; mute the kit and you get the one drop's skeleton back.
Practice: play the one drop first, then add kicks on 1, 2 and 4 without changing anything else. If the skank starts drifting toward the kick you have lost the feel — the chops stay short and off the floor.