The New Era 39THIRTY: the Official MLB Stretch Fit Cap

The 39THIRTY is New Era's reference stretch fit model for MLB. Its principle is unique within the range: no closure, no adjustment strap — the cap is made entirely from elastic material that naturally moulds to the shape of the head. Simply choose S/M or L/XL. It is the ideal choice for those who prioritise absolute comfort, whether for training, sport or long days out.

Stretch Fit: How Does It Work?

The stretch fit system requires no manual adjustment: the fabric itself stretches and contracts to adapt to your head shape. Unlike the 59FIFTY fitted which is ordered in a precise hat size, or the 9FIFTY snapback with its plastic closure, the 39THIRTY does not squeeze: it wraps. Key advantages:

• Zero pressure on the temples and forehead, even after hours of wear
• Stable hold without slipping, ideal for sport and active movement
• No adjustment needed: put it on and it stays in place

Which Size to Choose in 39THIRTY?

• S/M: fits head circumferences of approximately 54 to 57 cm
• L/XL: fits head circumferences of approximately 57 to 61 cm

If you are between the two sizes, go for L/XL for extra freedom and comfort.

39THIRTY vs Other New Era MLB Models: Which One to Choose?

• 39THIRTY: full stretch material, S/M or L/XL, maximum comfort with zero adjustment — the ultimate comfort choice
• 9SEVENTY Stretch Snap: stretch back strap with clip closure, structured fitted look, more defined style
• 59FIFTY Fitted: fixed size, perfect fit, premium finish — for purists
• 9FIFTY Snapback: adjustable plastic closure, flat brim, bold streetwear look
• 9FORTY Strapback: curved brim, soft crown, relaxed everyday wear

39THIRTY Technical Features

• Structured 6-panel crown in stretch material: flexibility with shape retention
• Curved brim: classic profile, optimal sun protection
• No adjustment system: fit entirely provided by fabric elasticity
• 3D embroidered logo on the front, MLB logo at the back
• Material: high-quality stretch polyester, breathable and durable
• Available in S/M and L/XL
• New Era authenticity hologram on every cap

Who Is the 39THIRTY For?

• Athletes who need a stable cap during effort without pressure
• Those who wear their cap all day and want zero discomfort
• Those who dislike adjustment systems and just want to put it on and go
• Those with head shapes that are tricky to fit with fixed-size models

MLB Franchises Available in 39THIRTY

• 39THIRTY New York Yankees: the timeless NY logo in the most comfortable model
• 39THIRTY Los Angeles Dodgers: iconic royal blue for West Coast fans
• 39THIRTY Boston Red Sox: MLB tradition combining comfort and authenticity
• 39THIRTY Chicago Cubs: a MLB classic in the most flexible cut
• 39THIRTY San Francisco Giants: black and orange, among the most requested

How to Care for Your 39THIRTY

The stretch material is particularly sensitive to heat. Hand wash only using a damp cloth and mild soap. Never machine wash or tumble dry: the elastic fabric permanently loses its properties. Air dry flat. Store away from heat and direct sunlight.

Explore the Full MLB Caps Collection

Find all New Era models in our official MLB caps collection, including the MLB Trucker cap, 9TWENTY Dad Cap and 19TWENTY retro.