ref b is the shit. it's a for sure in my stacks always. works best with any test for mass. ive injected twice daily for months at a time, never had any problems. it will also produce site growth because it's not bound to an ester. taken orally under the tounge works great as well. need to take twice a day though, it's in and out of your system at 5 hours tops. you can inject with a small gauge25 to 27 5/8 inch. it;s water based...