This is a small case for mounting and protecting the MaxBotix MaxSonar-EZ modules like MB1240 and MB1242.
The LV-EZ4 case http://www.thingiverse.com/thing:432967 will not fit since these designs has a large choke mounted on the rear of the PCB.
There is also an optional acoustic shield that protects against noise from propwash in addition to an optional mounting bracket for a bar.
If choosing the version with screws, two suitably long M3 screws are needed. If the shield is used, it will need the two holes to be tapped to M3.