SX90
SX90
Stephen Howard reviews the SX90 Straight alto at http://www.shwoodwind.co.uk/Reviews/Saxes/Alto/Keilwerth_SX90_straight.htm
SX90 DLS
SX90 DLS

"DLS" is "Dave Liebman Signature," introduced in 2011/2012. I quote from the Saxquest website:

This soprano was developed by a collaboration of Dave and the Keilwerth team.
The SX90 DLS is a cutting edge soprano saxophone which features specifications and designs set by Mr. Liebman.

These sopranos have a larger bore dimension which allows for a bigger more enriched sound, very warm in color.
The enlarged side keys in the right hand also make it possible for you to play the alternate F# and high F# key with the inner side of your fingers in addition to the traditional fingering method.

The SX90 DLS also includes a number of cork pads in areas traditionally occupied by leather.
Cork pads allow for a more positive feel and longer lasting durability.
The cork pads are a huge positive for the performance of the soprano, especially in the upper register where things can be more suspect for difficulty.

Like all SX models by Keilwerth these sopranos also features adjustable palm keys.

In our opinion this is one of the very finest sopranos made today. It is an incredible horn!

Keilwerth promo video.

SX90 II
SX90 II
The difference between the SX90 and the SX90 II soprano is the SX 90 II has two removable necks and the SX 90 has a fixed neck.
SX90R
SX90R
There are a bunch of "special edition" horns in the SX90R series:

* The 75th anniversary horns, celebrating Keilwerth's 75th anniversary in 2000.
* The "London" special edition tenor, which was an unlacquered horn with custom engraving made for http://sax.co.uk.
* The 20 Years Edition/SilverStar made in 2008 to celebrate the 20th anniversary of the SX90R.
* The Shadow Edition, which is made out of nickel.
* The Platinum Edition, a cool-looking horn that was platinum plated and had a custom engraving. I doubt I'll ever find pics of this horn again.

The essential idea is that you could/can get an awful lot of customization done from the factory.
Straight Eb Alto 98624
Straight Eb Alto 98624
Lacquer
From bigjoe772013 on ebay