Dear "To Be Announced"...
All the telescoping shroud does is lengthen the volume of the chamber so the muzzle exhaust has more room to expand and thus soften the muzzle blast of escaping air. This alone will quiet the muzzle blast somewhat, but not nearly to the extent that adding a quality moderator will give you.
The telescoping shroud has no baffles, and no sound buffering felt along it's chamber wall to effectively quiet the gun to where I would say it is "neighbor friendly". This phrase, to me at least, means that all the shooter can hear is the hammer slap on the valve, with literally zero muzzle noise resulting.
That is why I have always used an aftermarket moderator in my gun shy neighborhood. When I shoot, my neighbors cannot hear anything that indicates what I'm doing. Any sound that might reach them will be soft, muted, and not indicative of anything related to weapons. The only giveaway is the impact of the pellet/slug on target and even that can be muffled with the right kind of absorbent material behind the target to absorb the impact noise.
Do you really need a moderator? In the past twelve years I've put one on every pcp airgun I've owned. Personally, what I do in my backyard is no one's business but mine. That being said, I also want to be a considerate neighbor and not alarm anyone either...the add-on moderator covers both areas.
One last piece of advice, get one size larger than you think you need*. It's like a hose. If it's too short you can't stretch it to accomplish the job. If it's too long then you are covered and have a bit of overlap to boot, In obtaining silence, too much is WAY better than not enough!
Regards,
Kindly 'Ol Uncle Hoot
* One size longer/greater volume, i.e. don't use a .25 caliber moderator for a .22 caliber gun.