I'm not exactly sure what they're called in english... here they're called vipers. It's basically a metallic extensible cane (10cm un-extended with around 30cm fully extended) made to disable people. The strategy is to duck and hit people in their leg bones/muscles and it incapacitates them for a healthy while regardless of how strong you are.
I've seen people shatter rocks with them so stalkers should fall easily to these.
Here, i found a US website: http://www.selfdefenseproducts.com/S...s-p-16162.html