Question about proper orders for exiting spreads

After I sell an Iron Condor I would like to place orders to buy back each of the vertical spreads separately if and when the premium of each spread falls to a specific price.  Can anyone suggest the proper orders to use and why?  Thanks everyone...

You would use a limit order,  but in reality, if you are selling Iron Condors AND closing them out if they fall a certain amount then you are definitely sacrificing a good chunk of profit to commissions.      Even TK's uber low ones will start to add up on Condors that you sell and buy back.

That's 8 tickets total, added up to at least $45 in commission (for 1 contract of Condors)