This filter set includes a coarse particle filter (thicker element) and a hydrophobic fine filter (thin element).
Any blue paper inserts supplied are protective sheets used during storage or transport to safeguard the fine filter and should be removed and discarded prior to use.
For correct installation, position the fine (hydrophobic) filter first so it sits directly against the wire gauze screen. The coarse particle filter should then be placed on top of the fine filter.