Allen Tel Products AT580 RJ45 RJ11 Modular Connector Crimp Compression Tool with Trimmer Cutting Blade
Crimps RJ11 and RJ45 Modular Connectors. Made of Carbon Steel, Multi-Function Tool with Integral Built-in cutting blade for trimming. (this item is debranded and comes without the AllenTel logo or part number)
Note: This particular design is the most comfortable when prepping hundreds of connectors.