Beware whatever the percentage reduction may be, incompatibility with other kit is an important consideration!
I think I know what your saying here and it's a really good point, but on behalf of all the new bees that your comment might confuse, it will be worth me making what you mean a little clearer.
Mann lakes 'National' standard bee hive items will be fully compatible with anyone elses 'National' standard products, and their 'Langstroth' fully compatible with anyone else's 'Langstroth' products, and their 'National Hybrid' fully compatible with anyone's elses 'National Hybrid', and their 'WBC' fully compatible with anyone else's 'WBC' products' and finally their 14x12 National with anyone else's 14x12 National products.
As with buying anywhere, Just make sure before you buy from any supplier, the right product to be compatible with your own setup and you'll be fine as there is bound to be compatibility problems for example when you buy say 'National Hybrid' parts to go with your Langstroth and so on - that goes for any supplier isn't it.
If your not sure before you buy, call or email the company your looking to buy from and ask them direct - don't just go off hearsay or what you see on a forum.
I did mean to answer this point earlier in the year in a previous thread but I've bought some of Mann lakes really cheap supers & broods for use on the mountain this year and they were fine with our existing National items and they are bloody brilliant for the money and much better quality than what other bee companies sell their seconds for. We won't be making our own from now on to replace any old, falling apart national hives, it's just not worth it with Mann lakes low national standard prices.
