Here's what other sites are saying:
The Petzl Mini Prusik pulley features side plates that are designed to prevent a prusik friction knot from jamming the sheave while hauling.
A flat, swing-sided ball bearing pulley for use with a prusik knot, the Mini Prusik Minding Pulley from Petzl can handle big loads and is small enough to go where you go. This handy bit of hardwear can be combined with a prusik knot to form a jamming pulley system - very useful for improvised rescue in all climbing and mountaineering situations.
- Mountain Gear
This easy rolling pulley is light enough to carry with most places to make it useful in many scenarios. This pulley is designed to work in conjunction with a prusik friction knot for better rope control. a Special side plates designed for use with a Prusik friction hitch in progress capture systems a Sheave mounted on sealed ball bearings for excellent efficiency a Compact and lightweight a For use on ropes between 7 and 11 mm in diameter a Sheave: 25 mm a Efficiency: 91 %
With a super-light, compact design, the Petzl Mini Prusik Minded Pulley handles big loads but is still small enough to carry on your harness. The swinging aluminum sideplates and efficient sheave make it durable enough for big-wall use and light enough for just-in-case situations.