This extension lets you sample 3 feet deeper than the length of your sampling tube. (6 feet with a 3 foot tube) If you want to sample deeper than that you will need to purchase one or more JMC ESP Regular Extensions in addition to this extension.
In some situations, it may be expedient to plant several 2 inch diameter casings in the ground before returning to sample through each one. That is why we sell separate casings for the JMC 2 by 6 inch Concentric Sampling Tube.
Remember: This is the casing only. You should already have a Concentric Sampling Tube.