Stainless steel mesh filter guards with beautiful and solid design - Definitely Safe and Prevent baby shrimps/fish from sucking in the filter...come with 7 sizes in diameter. Please measure your filter intake diameter to make sure on the size:
9mm - Fit Zoomed 501, Boyu...and any filter intake with size 9mm
13mm - Fit eheim 2213-2215-2232, zoo med 511...and any filter intake with size 13mm
16mm - Fit any filter intake with size 16mm
17mm - Fit eheim 2217, Aquaclear 20-30-50, Rena XP1-2-3...and any filter intake with size 17mm
20mm - Fit any filter intake with size 21mm
24mm - Fit any filter intake with size 24mm
26mm - Fit Fluval C4..and any filter intake with size 26mm