The Tombow MONO Zero eraser pen is a lovely item. A neat retractable eraser pen 120mm long and approx 8mm diameter. Cylindrical elastomer eraser is 2.3mm diameter for precise erasing. Choice of barrel finishes. One of those simple but deeply satisfying little items. Also available with a broad rectangular eraser. Tombow Mono Zero Eraser Extra Fine Round Tip Single Eraser Holder from Towbow. Tombow's high precision eraser perfect for pinpoint erasing. Featuring a unique design the MONO eraser's high performance changes the concept of detailed erasing. Contains a short-pitch knock mechanism that extends the eraser by only 0.7mm with each push. The ultra-fine 2.3mm eraser is perfect for fine detailed drawing. This set contains one eraser holder. OMGHOWCHEAP are the UK's largest online independent stationery retailer, offering over 3000 brande. Tombow Eraser. Nib Type: Round Tip . Shape: Round. Colour: Multicolour.