Review on Sterling Seal FI 0404 SP1 Purolator Mechanical by Joe Fulce

20 pieces ordered 24 x 4 which is not as easy to get as some other sizes. These are Purolator branded filters and appear to be of excellent quality. I wanted a very low pressure drop filter for my new ECM forced air oven and the specs for this filter on the Purolator website say the pressure drop is about 0.19 water column. I tested the filter on my system and it showed 0.20 water column at a higher flow rate than tested. This is an excellent result and a very low filter pressure drop! For comparison, I used to have a standard 1 inch filter in my system that gave a 0.40 pressure drop when new. A high pressure drop filter at the furnace inlet is bad news, wastes energy and can shorten the life of your fan motor and entire system if airflow is too restricted. Quality cardboard on top, folds are separated by cardboard V-notches. To be consistent, the exit side has expanded metal on the front for security and integrity. I am very very satisfied with the purchase, the delivery is fast and reliable, no damage.