A 5/16 in bolt with national fine threads will have:
A) 24 threads per inch. B) 20 threads per inch.
C) 18 threads per inch. D) 16 threads per inch.
Question 2
Flex duct is easy to install, quiet, but has higher ________ than all other forms of duct material.
A) installation cost B) efficiency ratings
C) energy loss D) resistance to airflow