i have Crabel's book and even phoned him shortly after i bought it , nr7 means narrowest range for 7 bars , there is also , id , which means an inside day (lowerhigh and higher low than previouse day), but if using intraday one might call it ib , inside bar , he also talks about idnr4 which is both narrowest range for 4 days and an inside day , which produced slightly better results than each individually , but not by much.