help for a beginner - which coupling is better

hi,
i would like to get your opinions on which coupling is best suited (considering value for money) for joining 8'' PVC pipes underground (for sewers). I should mention that it is intended for a factory in mexico so we will be using american products which i'm not familiar with (and that is why i need your advice.
thanks

WELL as long as this sewer doesn't see any temp.s above 200 Deg.s F then "cheaper" is normally better. That being the case why are you using couplings at all? Normally for underground PVC lines they use a "bell-n-spigot" design, so avoiding couplings altogether. But even that has been replaced with a fusible PVC which also avoids use of couplings and makes installation even faster ...see link ( www.undergroundsolutions.com/direct-bury.php ) ...Good Luck!

Jop, 11echo thanks for the speedy reply.

i'm considering the Top Bolt by Smith-Blair, theMacro by Romac and the Hymax by TPS.