Amati-Kraslice has made a variety of mouthpieces over the decades, ranging from pre-war styles carried over into the 1950s, proprietary designs through the 1960s and 1970s, Vincent Bach imitations from the 1970s to 1990s, and various specialty models throughout.  

This 1-1/2F [1.5F, 1½F, 1 1/2 F] flugelhorn mouthpiece features a Large Morse taper shank intended for Amati's oversized receivers, similar to the Conn 1F Vintage One model.  

Amati's 1-1/2F was based on a purpose-made design from the 1980s or 1990s, which was effectively a flugelhorn cup with a shaved-down trumpet blank.  

When Amati introduced the heavyweight [Yamaha-esque] "Virtuoso" series in the 2000s, the design was modified to the form we see here.  It's still made today, and is standard issue with the AFH-201 [B-226] & AFH-204 compact flugelhorns, AFH-601 & Cerveny VFC-FH6232 tall-profile flugelhorns, and the ABG-201 clairon bugle.  

The rim diameter is close to the Vincent Bach 1-1/2B.  The cup shape is more akin to a deep cornet type, more so than many flugelhorn mouthpieces - if a Bach 1-1/2A existed, it would be close to this Amati-Kraslice piece.  

Strangely enough, the Amati's close to the Martin 1 cornet/flugelhorn pieces, the Getzen version of the 4B, and is a bit smaller than the Denis Wick S soprano cornet.  The Amati is actually a bit shallower than the Bach 5V and slightly deeper than the 5A, 7A, and Yamaha 8E2.

Why is that?  Christine Derksen of Conn Loyalist and others have mentioned that European flugelhorn repertoire often has melody/descant parts in a rather high register, compared to American jazz/marching band flugelhorn parts.  

For instruments designed in Europe, this makes sense to include a medium-depth mouthpiece as a compromise.  The A&S 6T is an even shallower V-funnel mouthpiece in that vein.

While this mouthpiece probably won't turn you into Chuck Mangione, it does sound a bit clearer than massively-deep Oakes and Courtois pieces.  The sound is closer to Bach-style flugelhorn mouthpieces, but not bad.  The large rim takes chops and lungs to control, but overall it's a nice piece.  I personally find it far too wide for comfort, but it might be fine for you!  

This example is not explicitly branded and was probably intended for a stencil horn, but is unmistakably Amati-Kraslice manufacture.  It has nicks and some light scratches on the rim, and the machined "frosted" finish is in good shape.  The shank opening is decent and mostly round.  It's ready to play!

Note that it has a Large Morse taper shank and isn't well-suited for Small Morse receivers.

  

Sold as-is, no returns, pay within 3 days.  US shipping free - caveat emptor as we cannot take responsibility for any mishandling/loss on the part of the courier at any point - this is FOB shipping point.  By buying, you [the buyer] agree to the potential risk of the package not arriving due to courier mishap - be aware of these conditions.

Usually we get the item in the mail within 1-2 days.

Please note shipping delays may still occur.  It could take ~an extra week in some cases.