^^^Confusing, to me. Without a filter dissection (cut open), impossible to definitively say what type of compression spring a filter uses. 'Visual inspection' down outlet hole will provide bypass location (if one spec'd) and centertube type info, not compression spring type. So seeing a "stamped leaf' compression spring vs Wix/Napa Gold typical coil compression spring not doable otherwise.
I do note now that a 'not topic' 5/1334 was brought into the discussion. That NG/WIx Labeled application has been discussed here often. That application used on Hy/Kia, M&H (Wix parent) decided to combine with it's Hy/Kia Korea OF production and as seen in multple dissections here 'it' does use a leaf spring. Again though that's not topic filter made by Champ Labs. Asa an aside, based on comments here most seem pleased with newer 5/1334.
Another possibility on topic filter, this specific topic "NG" (not Wix labeled 51516) application, subbed to Champ Labs. Also very unlikely I'd think, but can't rule it out based on topic filter.
I've seen Napa Gold/Wix labeled 'spin on' automotive application filters made in Mexico. The NG1334 made there at one point, c&p'd one. I've seen Napa Gold/Wix center tube with holes. I've seen NG/Wix labeled using louvers, especially since M&H acquisition. Used both and all made by Wix. I've never seen a Napa Gold spin on filter made by Champ Labs before, either on this subforum or in real life.
Local Napa now having semi annual Gold sale, while I won't purchase plan to ask to see topic NG1516.