CLEAR PRINTING – Bigger compatible Pyramid 4000R ribbons adopt high-density Nylon, combining with advanced ultrasonic welding technology, which makes the ribbon flatter and produces crisp & rich prints. | LONG LASTING - Bigger ribbon features specially formulated inks with custom lubricants, which can be absorbed evenly by ribbon and keep good humidity, to ensure the highest quality compatible ribbon for your machine. | FULLY COMPATIBLE - Bigger replacement for 4000R calculator printer ribbon is adopted with precise specifications to allow for seamless installation into your printer. | COMPATIBLE MODELS – Work for Pyramid 3000HD, 3500, 3700, 4000, 4000HD Time Clocks. | 100% SATISFACTION GUARANTEE - 365-day Money Back & Lifetime Warranty Guarantee on All Bigger brand products which cover any quality, reliability, and performance issues.