The OTR. Mop / Marker Pack is a great way to sample some of the best empty markers available on the market. This pack features the famous (1) OTR.001 (Soultip), (1) OTR.004 (Soultip squeeze 70ml No logo), (1) OTR.060 Jumbo Marker, (1) OTR.160 (mini pump maker) and (1) OTR.006 Steel nib (Soultip 15ml). The Mop pack is a convenient and cheap way to find out why the On The Run markers are so famous. These mops ship EMPTY! For optimal performance refill them with OTR.401 Paint or OTR.484 Flowpen ink. OTR. paints and inks are vibrant and wildly effective.