Snap Dragon Doubles

This is a little known treatment or convention, if you will, with a certain interpretation. First, let us see it in action.

North 1H

East 2C

South 2 D

West DOUBLE

North 1C

East 1H

South 2D

West DOUBLE

The normal significance of the DOUBLE by West in Fourth Seat after the first three players have all bid a different suit is: Before using Snap Dragon, both partners should agree: 1. at which Level this convention still applies, generally to the Two-Level. 2. upon the strength at which this convention can be applied at which Level. 3. to make it part of their Partnership Agreement