A connection for releasable connecting confronting first and second portions of first and second members. The first portion has a first passageway has a second portion has a second passageway. An elongated coupler member is in the first passageway. A shim projects endwise outwardly from the first portion on one side of the first passageway. A coupler member is extendable endwise outwardly from the first passageway beyond the shim.When so extended, the coupler member is insertable into an entry portion of the second passageway. The first portion is movable relatively towards the second portion when the coupler member is extended. The extended coupler portion is moved into and through the entry portion of the second passageway. The shim is moved into the entry portion of the second passageway along side the coupler member. The second portion and the coupler member have confronting first and second lock surfaces that make contact with each other and hold the first and second members together when the shim and coupler member are both in the second passageway and the coupler member is retracted.