marineland bulkheads - are they different?

[corpusse]

i got them sealed with the help of the wrench, very tough to access. I've never had problems like this with bulkheads before. Always hand tightened except for the very first ones I did because the megaflow kit came with that pvc wrench which i couldn't find so had to spend $25 on a wrench for two 1/4 turns