ClipMate uses a relational database engine called DBISAM from www.elevatesoft.com.
It stores data in a series of files with extensions: .DAT, .BLB, and .IDX. If you see files with an extension ending with the letter K, then those are "backup files", and can be deleted. They occur during database repair/compress operations.
In order to have a valid ClipMate 6/7 database, you need all 24 files.