Book Dart is WAY more than just a bookmark.  It is a paper thin, precision cut, smooth metal* clip that slides on and off the page at your exact lines AND without ever leaving a mark. (*phosphor bronze, brass or stainless)
 
It will be visable at page edge even when your book is closed, is "A C" (ahem, "archivally correct") and can be moved elsewhere or left in place for you or someone else to rediscover your reading discoveries.  
 
This item is book safe, never harms the page.  A safe alternative to paperclips, underlining and highlighting. Will not stain.  Please keep away from small children
 
Size: 4 1/4" x 2 3/4".
Made in United States
Weight: 0.2 oz (4.5 g)