Vater has the most durable, best playing sticks I've ever played. So usually I buy them per dozen, which is one casing in drumstick land.
Unfortunately I never receive an unopened casing from Thomann, they just grab 12 pair from the warehouse and put that in the shipping box.
Now, the last time I received my 12 pair I noticed very large weight differences between the sticks of a "matched" pair, and I have noticed that earlier with other pairs. They play different, they feel different, they break different (good Vater sticks never break, they just erode over time). So I decided to grab a scale and compare the weight of the sticks from the same pair. Most pairs had a difference of about 2.5 and 5 gram (a stick is around 70 gram). The lightest was 62.4 gram, the heaviest stick was 78.3 gram. That 's a whopping 16 gram difference! Both being 2B sticks from the same order but from differents pairs. The largest difference from the same pair actually was 78.2 vs 62.4.
Now, I will keep playing Vater sticks, but from now on I will be returning any received pair with large differences and sticks weighting less than 70 grams, as I find these to be unplayable and very undurable.