Acrylic Pyramid Grinder with Magnet. Acrylic grinders like these are great for three reasons: firstly, the pyramid shaped spikes make easy work of even the most stubborn herbs. Secondly, the magnetic pads on both sides of the grinder help ensure that the two halves donâ€™t come apart when you are using it or when it is in your pocket. And last, but by no means least, having a compartment to put your herbs in isn’t a bad idea either as it means you donâ€™t need to carry around a separate baggie, whether you keep your herbs in their original state or pre-crumbled itâ€™s safe and ready to go in your stash compartment. Available in various colours.