Per this site, they look to be interchangable:
http://www.bbqequipmentstore.com/Maverick-ET-732-ET-733-Hybrid-3-foot-Probe-ET-732-ET-733-Hybrid-3-foot.htm
The replacement proves I bought from them, when mine read LLL, were only $9 but look like they went up a little. $14.99/ea
This link has...