CHESSTRONICS TACTICS BOOKS ARE 6 CATEGORIES . Only Pack of 10 items are available. 

STEP1 - BEGINNER
STEP2-U300 - INTERMEDIATE 1 
STEP3-U600  - INTERMEDIATE 2 
STEP4-U800 - ADVANCED 1 
STEP5-U1000- ADVANCED 2 
STEP6-U1400-  CLASS-C 
STEP7- 1400+ - CLASS-B & A