Detail 01
.624 inch cup diameter
Small for a trumpet. Less lip vibrates in the cup, which favors the top end and thins the bottom.

Independent shopping perspective
Silver-plated Schilke 5A4 trumpet mouthpiece. Small cup diameter, shallow A cup, semi-flat #4 rim. A specialist high-register piece, not an all-around one.

Strong match
Consider the trade-offs
What matters in use
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 01
Small for a trumpet. Less lip vibrates in the cup, which favors the top end and thins the bottom.
Detail 02
The shallowest cup Schilke makes. Brightens the tone and stacks the upper register at the cost of volume and depth.
Detail 03
Semi-flat cushion contour. Spreads pressure across the lip, so endurance holds up over a long set.
Detail 04
Schilke's standard throat size. Keeps resistance normal so the shallow cup doesn't feel choked or backed up.
Detail 05
Grips the lip more than gold and costs less. It does wear through over years of daily playing.
Final check
Product questions
Straight answers to the questions shoppers most often ask about this product.
Yes, it's a standard trumpet shank and seats in a standard trumpet receiver. It will not fit a cornet, which takes a shorter, smaller shank.
No. The small diameter and shallow cup reward a developed embouchure. A student is better served by a medium size like the 13, which has a rounder rim and a C cup with more volume for tone.
The 6A4a is slightly smaller at .630 inch with a 27 throat and tight a-backbore, built for extreme high register. The 5A4 is smaller still in diameter but uses the more open 26 throat.
Plating changes feel far more than sound. Silver is grippier and firmer on the lip; gold is slicker. Rim contour, cup depth, and throat drive what you actually hear.
Reference
The complete catalog record, organized around the decisions musicians make when comparing gear.