Hello, how are you? Thanks for reaching out. The DEMO version has several limited features.
Although the plugin is designed to affect all your equipment when hit, you can modify its values with, for example: <damaged-value:rnd(x,y)>
, which will allow you to make it receive random damage. You can set it to receive between 0 and X, so there is a chance that the equipment will not take any damage.
Best regards.