I'm looking for some black elastic hook covers that come with the Blackhawk slings. I have found some short ones from Blue Force Gear, but I'm wanting some longer ones over 3" long. Similiar to the one in this pic. Any help would be greatly appreciated. Thanks.

http://i115.photobucket.com/albums/n318/LVdubbin/18-1445-IMG1_L.jpg

The nice Korean lady at the drycleaners will gladly sew that elastic you bought at JoAnn Fabrics into a tube for a few dollars.

What is that material called?

Elastic.

It's called "elastic".

You could just whip stitch the ends together yourself or have mom/sis/Mamasan run it through a sewing machine in about 15 seconds.
A yard of 3" black elastic, a packet of needles and a spool of black thread is going to come in under $10 just about anywhere.
The taupe color they sell for underthings is a fair approximation of khaki/sand/FDE if that's your bag.
Some place like Supply Captain might even have it in honest to goodness camo colors.
Some places might have 4".

Go down to your local fabric store, it's full of broads. That's where they hang out.
They like showing men how to sew like we like showing them how to shoot.