Sentrilock is a better lockbox than Supra. It’s much EASIER to use. The key is a credit card (no charging & no cell signal needed) The key holder stays attached so no more fumbling with loose parts. You can set temporary codes so contractors or agents who forgot their key card can get in and your listings will never miss a showing. Codes can be set from your smart phone. Tracking of showings. Much Much More! Oh, did I mention Sentrilock is CHEAPER than Supra too!?! The more boards who use it, the cheaper it is for everyone! I, Michelle Pursell, Reliable Realty, Inc., used this in Indiana and it only cost us $25 each! Sentrilock traded for agents’ old Supra boxes too! Most states use Sentrilock as Supra is outdated & not user friendly.