Buying Replacement Disposable Blades for a Straight Razor Handle

I am new to using a straight razor and am starting with a disposable. I just used my last blade that came with the razor and am wondering where to buy more of the single edge blades that are the full length of the razor. This is what I'm using: The Art of Shaving - Disposable Blade Straight Razor - Browse Thiers-Issard Razors

The Art of Shaving store sold me replacement blades that don't fit well into the razor and that are only half as long as the handle. I have looked everywhere online and a lot of sites don't specify the length of the blade. Anyone have experience with this? Thanks.

it's a Dovo shavette. I imagine Dovo should make the exact replacement.

With your shavette, there should be a black plastic clip as well as a red plastic clip. The longer blades will fit in the black clips while the shorter "regular size" double edge blades will fit in the red clip. Personally, I never use the black clip. The double edge blades are a much more easier size to maneuver with, especially when you are just starting off.