Its hard to tell from the picture but there is a groove for the o-ring.

Most plates you get from other shops don't have the o-ring groove machined into the plate and want you to use RTv to seal, just stick with the stock o-ring and keep it sealed up nicely with our block off plate.

Fits all 84-88 13B Mazda Rx7 turbo & non-turbo front covers.

Make sure you premix your gas if you intend to use this.