Is this an illusion?

Can someone tell me how this underlayment is attached and why those bundles don't slide off.

When you stack tile on a steeper pitch, you make "tables" of tile to stack them on like this;

I always stress that the "leg" of the table be locked by being firmly against the batten, but I frequently see competitors that are rather lax about it and hope to see the avalanche come crashing down. Never seen it happen, but I've seen the results of it having happened numerous times, (bowed out gutter, piles of tile on the ground).

It's actually refreshing to see a guy working without ropes around his neck, but I have to say I would never carry a bundle on my shoulder on that pitch. Lower the center of gravity and carry them with two hands. That's my opinion and I'm sticking to it. I would never load that way either. They should be resting against the stickers. They make brackets for 2X4's laid flat. Very light, very easy to install. Why risk a chain reaction that tears the gutter off the roof. jmo.

Good 30# installed with a bunch of slap staples. "cts racing" is right about the nails holding the bundles[size=3][/size]

2 sided grace I&W :woohoo:

My guess is there is a 8d / 16d nail at the bottom of each package.

Velcro