OK, you guys are confused (except you, QP
)
The ND LPR
is a Jackhammer, integrated with a front cap for your impy in an aesthetically pleasing way.
The SP LPR is
not a Jackhammer, the JH is made by ANS and the SP one is made by SP (well duh.)
The Jackhammer is certainly a faultless performer, as is the Palmer Microrock. The SP LPR has the advantage of being a good deal smaller than either of these, and from seeing Phil Webb's at the M25 it certainly seems to do the job.
The Evil Respirator is an integrated LPR with no hosing to get shot, but it does reduce the air volume behind the valve so is best used in combination with an Evil Valve, and run at a higher valve pressure than normal for an Impy, but still with a low LPR pressure driving the bolt.