Once the code is inserted and saved, refresh the GSDT to run the test again to ensure that the product schema and aggregateRating is showing up well. There should not be any errors present in the schema In cases where metafield is not present in a Shopify store (syndicated stores) A different set of rich snippet codes needs to be installed, which rely on pulling the review data from widget directly instead of the Shopify metafields:

Puffco Peak Replacement Bowl

Sale price $15.00
Shipping calculated at checkout.

Puffco Peak Replacement Bowl
Puffco Peak Replacement Bowl

Tweak your Peak!

The Puffco Peak comes with a ceramic bowl for the atomizer and now you can try the Quartz, Titanium, and Silicon Carbide (SiC) buckets too! Simply drops in place of the stock bowl. 

Pictured (from left to right): Ceramic, Quartz, Titanium

Silicon Carbide (SiC) bucket is now available! (Not pictured).