Counter for six long, cylindrical objects such as bottles, pencils, or rolled items. The reading ろっぽん is a euphonic change from ろくほん.
There are six bottles of beer in the fridge.
鉛筆を六本ください。
Please give me six pencils.
六つ is the general counter for six items, while 六本 is specifically for long cylindrical objects.
六匹 is used for six small animals, fish, or insects, whereas 六本 is for long cylindrical inanimate objects.
julienne strips; long thin strips
Compound of 六 (ろく, 'six') and the counter 本 (ほん, 'long cylindrical objects'), with the regular euphonic change of ろくほん to ろっぽん.