This fits below the body of the seat. Dies anybody know what is the part number for the same or what is it called in the catalog

 

http://www.lexussouthatlantaparts.co...driveLine=8088

Neither your signature, nor your post indicates what year your vehicle is. You also don't indicate which seat (driver or passenger). However, I've attached a pic of the driver side seat assembly for a 2010. In that pic, I don't see a similar part to the one you provided. It looks like a filter of some type. Are you sure it's part of the seat?

 

Look at the diagram roadfrog posted part- 88921D looks like it might be what you are looking at. Do you have any other photos of the part? Do you have the cooled/vented seats?

 

That lists as a filter, but unless it's my crappy eyes, it doesn't look the same as the pic. If it is the same part, it's cheap.....12 bucks.

 

I'm still very skeptical on it as well. They really don't look that close. That's why I was wondering if OP had any other photos possibly closer and different angles.