use this to keep your book open with one hand R2 has a .12" hole for a book mark / keychain Also the thumbhole is reshaped a bit for a tight fit (on me) similar to http://www.etsy.com/ca/listing/171764689/book-holder-cherry-wood-delivery-in?ref=related-0 R1 sized for my thumb. 0.9" x 0.8" R2 with 0.9" x 0.95" and 2 degree draft. should be rescale to your thumb.