That's 84 requests blocked (54% of the page, 14 domains blocked out of 16)
To do this, in Advanced User mode, under 3rd Party Scripts and 3rd Party Frames, click the left-most cell pair to make them red. (right-most pair is settings for the current site only, left-most pair is for every single site, ie default settings)
lol, and fake animated popup alerts telling you what other customers are buying right now? Is this really a site for savvy electronics hobbyists? It feels like the crappiest web2.0 "seize them by the eyeballs and don't let go" garbage site possible.
Absolute horror! Auto-playing video with sound on by default, hundreds of requests to remote servers (Google Play, Youtube, AdSense, some unknown domain, ...).
I respect Arduino for what they have done for the maker and tinkerer scene, but landing pages like that will not keep me as a visitor.