This comparison is no longer valid due to design changes to the Halcyon 30Lb Eclipse wing in 2019. This is an old post and applies only to previous generation (before 2019) wing designs and is for past reference only.

You can read the Halcyon New Design Update from July 2019 online. Or visit our current Halcyon Single Tank Wing System pages. 

One of the most Frequently Asked Questions we received this summer was “what size wing?” for single tank diving, particularly when it came to choosing our all-time best seller Halcyon Eclipse Wing Systems.

It’s always a difficult one given that as divers we?re all different and so is our background, training, trim, equipment and cylinder configuration – the conditions we dive in.

So it’s not our place to advise on how much lift any diver and his/her equipment needs although we’ve always tended to favour the minimalistic side ourselves as users of 40Lb Halcyon Evolve  wings for twin 12 twinset diving with aluminium stages, knowing it has plenty of lift. Then again, there is so little size difference between the single tank Eclipse 30 and 40 that it really boils down to personal choice.

The simple social media answer for wing sizes would be enough lift to keep the divers head comfortably out of the water and provide ample flotation for his/her equipment and accessories on the surface (without the diver in the wing).

But these explanations and many expert opinions we come across suggesting an even more Alpinist approach don’t necessarily explain what “enough” and “ample” mean in context and never seem to take into account adverse conditions on surfacing.

Underneath we have depicted comparative dimensions (pre-July 2019) and appearance of two leading wing sizes.



The Eclipse wing actually comes in 3 sizes, the (tropical) 20Lb lift slimline version and the 30Lb and 40Lb lift single tank wings. We stock the latter two which are the most popular ones globally with demand for the 30Lb lift exceeding demand for the 40Lb on an annual average – and order in specially the 20 for divers who require minimal lift.

The difference in lift between the 30 and 40 may be 10Lb (4.5kg) but that doesn?t exactly translate in a major size difference so we won?t go into the age-old argument of how streamlined either is. Obviously the 30 is marginally narrower than the 40 in all dimensions but with a maximum difference of under 5cm the final choice is with the user.

And given there is no difference in the price, it really is the divers decision whether to have that extra bit of lift to maintain a higher profile while on the surface, say in adverse conditions, an arguable advantage in any rescue situation, or to support heavier kit configurations.

You know your own kit, your own diving conditions, trim, comfort zone and how much lift you want out of the water so hopefully the pictures below and the specs we’ve measured will help with your decision:

Comparing the Eclipse 30Lb and 40Lb side-by-side


Comparing the Eclipse 30Lb and 40Lb wings (flat out specs)

Comparing the Eclipse 30Lb and 40Lb wings (fully inflated)

Comparing the Eclipse 30Lb (top) and 40Lb (bottom) Eclipse wings

Comparing the Eclipse wings width difference (deflated)

Comparing the Eclipse wings – side view of inflated 30 &40Lb