Yep its a solder, made in China. Most likely a common tin-lead solder, though the importers no where give the chemistry. Biggest issues I would have buying this stuff is:
1. The almost hokey advertising - no where is it called a simple lead based solder, the advertising has this "gee-whiz, super material" tone to it.
2. Mainland China origin.
3. The fact that the poster touting this stuff spams the forum every time a bimetallic question comes along, with the same "gee-whiz" tone used in the decidedly overwrought advertising.
http://www.breckocorp.com/magna51.htmhttp://www.magnagroup.com/products/magna/pdf/literature/dis_51.pdf