similar to the ring 22 except that it has a different type of retaining means the ring 22a has an axially extending hole 24a which contains internal standard threads 26a which match the standard external threads 20 on the fill fitting 12 the ring 22a has non standard customized external threads 28a similar to the threads 28 on the ring 22 which match the threads on the collar in fig1 instead of the pin 32 shown in fig1 the ring 22a has an inwardly facing slot 50 which opens into the hole 24a located within the slot 50 is a cutting tooth 52 attached to a leaf spring 54 by a rivet or by other suitable means the leaf spring 54 has one tooth retaining portion 54a and a wider portion 54b which is wedged into the slot 50 to resiliently hold the tooth 52 therein as may be best seen in fig5 the tooth 52 is shown in fig3 and 4 with a sharp point extending into the hole 24a when the ring 22a is screwed onto a fill fitting by rotating it in a clockwise direction the spring flexes and allows the tooth to be moved up into the recess 50 by the external threads on the fill fitting if an attempt is made to unscrew the ring 22a from such fill fitting by rotating it in a counterclockwise direction the pointed end of the tooth 52 will dig into the external threads of the fill fitting and damage the threads to make them unusable if the adapter ring 22a is removed in fig7 and 8 another modification of.