What are the differences between these two ACDELCO shocks?

[abdullah_Zahra]

So, my mechanic told me that my shocks were bad and in need of replacement. I have no idea about different styles and models and features of shock absorbers. I think my 1500 suburban (2010) comes with these OEM shocks:
(540-435)
However, I found them to be way out of my budget right now and instead I found these "heavy duty" shocks on ebay, also from ACDELCO for much cheaper.

The seller insured that these would fit my vehicle as well. The only concern I am having is what could be the difference between my current shocks and these "heavy duty " labeled shocks? Why is there so much price difference? And what does gas charged shocks mean sorry, a newbie question

 

[OR VietVet]

The 540-435 is a rear shock and listed for the ZW7 RPO code. The other shock in the picture is a front shock.

You are not supplying enough vehicle info and RPO code information to be able to compare at ebay. What ACD part numbers at ebay?

The gas charged shock will have constant outward pressure to help keep the tires in contact with the road.

By the way, all shocks are listed at the very least as "heavy duty". I have never seen a shock listed as "light duty".

 

[Joseph Garcia]

Post up a photo of your RPO code sticker from the inside of your glove box, and post your VIN number. Then, we can help you identify the correct part numbers for your truck.