Cheaper offering of Tiffen Polarizer filter

[EL Pistoffo]

On SRPs website they list a 55mm Tiffen circular polarizer for the GoPro hero3 for $40. 55 mm Tiffen Circular Polarizer Filter

On amazon they list a 55mm Tiffen circular polarizer for $11.95. Amazon.com: Tiffen 55mm Circular Polarizer: Camera & Photo

Are these the same, or close enough, filters? By the closeup images they look nearly identical except the amazon version has threading to stack another filter and no white edge.

My intention is to use it on the SRP Blurfix3 mount. I very much wouldn't mind saving $30 for the same product.

SRP claims their version is ultra-low profile to eliminate vignetting. Whats your take on this?

SRP Tiffen Polarizer


Amazon Tiffen Polarizer

 

[dfx]

If you don't mind some seriously slow shipping, you can go even cheaper.

Jeryerce 55mm Circular Polarizing CPL Camera Lens Filter - DinoDirect.com

However, I have no idea about the vignetting issue.

 

[fbk]

SRP claims their version is ultra-low profile to eliminate vignetting. Whats your take on this?

That's why they have machined the front of it off leaving the exposed silver rim that you can see in the top pic.

 

[EL Pistoffo]

That's why they have machined the front of it off leaving the exposed silver rim that you can see in the top pic.

Well that answers my question.
Thanks