These are lightweight static blocks with an integrated becket that can be stacked together to provide a purchase system from 2/1 up to a 5/1. They are designed for slippery lines like Dyneema and offer a very strong and simple alternative to bearing blocks. Stackers are a great solution for challenges that offer a high load/low travel or a low load/high travel situation where their simplicity and lightweight are beneficial.
These blocks are designed with a V-style groove to minimize friction
Can be used with a soft shackle or spliced directly into a running back or other rigging for an integrated purchase system
Lashing holes included for securing the running line
Dynamic line can be run to a cleat or lashed off on the system itself