EJ-7 interlock

An EJ-7 interlock is an engineering tool used to access or close panels. It is made up of tritanium composites. With an EJ-7 interlock, one could access every critical system on Deep Space 9.

When Miles O'Brien was assisting Neela in repairing a system in Odo's security office, O'Brien remarked that an EJ-7 interlock would be required to close the panel they were working on. While looking for the interlock in his kit, he realized that it had gone missing. After a search, they found it in an access tunnel, melted into slag due to exposure to plasma. 

EJ7-Interlock