Used to clean the thermal print head. This item looks just like a marking pen or highlighter and has cleaning solution in it. Specially designed to remove ink, dirt and contamination buildup on thermal print heads. Allows printer to print cleaner, clearer and crisper. Just swipe cleaning pen across entire printer head surface. Use every time paper stock is changed RoHS Compliant. Shelf life: New and unopened 2 years. Opened and cap replaced correctly 6 months. Opened and cap not replaced correctly 1-2 days. 12 per box