a tubular breech lock box connector 58 extends outwardly from the main housing 50 as illustrated in fig1 and 12 the breech lock box connector 58 defines an interior bore 60 having a plurality of inwardly projecting ridges 62 the ridges 62 are spaced apart from each other both radially and axially within the bore 60 preferably the interior bore 60 also includes an annular fluid seal 63 fig8 that creates a fluid seal against the stinger 30 when it is inserted into the bore 60 in addition the interior bore 60 also presents a row of inwardly projecting anti rotation locking dogs 48 the dogs 48 are meant to be complimentary to the anti rotation dogs 47 of the breech lock barrel 34 fig9 and 10 illustrate a locking pin 64 which is preferably used with the cement swivel 16 and is used to lock the stinger assembly 20 into a coupled position with respect to the cement swivel 16 the locking pin 64 is preferably retained by a sleeve 66 and is axially shiftable between two positions in the unlocked position shown in fig9 the locking pin 64 does not prevent rotation of the stinger assembly 20 with respect to the cement swivel 16 in the locked position shown in fig1 the locking pin 64 is disposed within an indentation 40 of the flange 38 and will prevent rotation of the stinger assembly 20 with respect to the cement swivel 16 in particular embodiments the locking pin 64 has a.