That one looks to be splined Allan, make sure the implement end of a slip clutch is compatible with the input shaft of the implement. Some input shafts are round, some are splined. If you're not sure, the bottom of that AgriSupply slip clutch is the implement end. I'm pretty sure it's splined.
http://www.ptoshafts.com/newpage31.htm has a very good selection of both splined and shear pin (round) styles.
//greg//