The vest is very durable and good quality. I looked all over the place for a vest within an affordable price-point, and this one fits the bill perfectly! Its not too great for running since it shifts (even on the tightest level) but if you flip it upside-down, it works pretty well! Its secure during strength training and breathes pretty sell since its the minimalist style. As a personal trainer, I wouldn't typically suggest 12lbs to start, but if you're up for the challenge, go for it! It'll definitely make a difference in your workout and though your muscles may hate you the next day, your heart rate will appreciate it! :)