Compact Pack: Classic style kraft paper index cards. 6 pack with binder ring for easy use. Classic Design: For easy sorting and safety use, all cards are shaped to rounded edges and feature a pre-punched hole. Comes with 6 rings for easy classification so you could easily keep them neat and organized. Each card measures 7*4cm/2.7*1.5in. Premium Quality: Thick cardstock plus anti-corrosion binder ring. Bound with front and back cover. Easy to use and durable. Study cards can be printed in a standard printer. Apply Your Own: With a marker you could easily apply words, numbers and equations on these double-sided cards, make your own demonstration and education kit. Perfect For: Home and preschool education on teaching, reviewing and practicing. Could also be used as notepad, memo.