Rapidprint C724 Ribbons 12-Pack Rapidprint C724 Ribbon 1121-0277 Rapidprint C724 standard Cotton ribbons. Two spools, double-size (two spools on each spool), Purple ribbons. Box of 12. Our Price: $192.00

Rapidprint C724 Purple ribbon                          

Part Number:  1121-0277

Dual-twin black spool ribbon fits the (discontinued) Rapidprint C724 automatic date time and numbering stamp. 

It is also called by government offices - a "book and page machine".
Found across the nation in government offices.   Twin spools - two across and two down.