NOW Trodat 4913   Impression Size: 7/8" x 2 3/8"

(Equal to MaxStamp SI-30) Self-Inking Stamp. All Self-Inking Stamps use a Rubber Die Plate and Replacable Ink Pad. Specify Ink Color: Black, Blue, Red or Dry Pad (For Inking in Another Color)
Impression Size:7/8" x2 3/8"

See Ink and Accessories, then, Replacement Pads, then, M Series Stamp Replacement Pads.