Merkury adapter question

[LMarge]

Hi everyone!! My sis and I both were blessed this Christmas with new Canon XTi cameras. She also recieved this lens adapter -- Merkury Optics 58mm wide angle with macro. We're not sure what it's for!! A little help and advice for when to use it would be great!! She didn't ask for it - it arrived as part of the package her hubby got her. I know it's an adapter and screws on to the front of the lens, but we're not sure which lens to use and if you're suppose to use them together or separate - we're a bit camera equipment stupid at the moment!! Thanks for your help!
Blessings,

 

[LMarge]

Okay - no replies!! Maybe I should just ask if anyone has ever heard of Merkury Optics? and what are thier products like? Did she get something that's totally useless?

 

[My2Girls66]

Does this help? Have fun with the new cameras
http://stores.channeladvisor.com/Digitalet/items/item.aspx?itemid=98731

 

[LMarge]

Thanks so much! That does help explain what it's for! I'm just upgrading from a Canon S2is to the DSLR world and my sis is moving up from a small point and shoot! Talk about two people in over our heads!!! Thanks again for the link!
Blessings,

 

[My2Girls66]

You're welcome