This is Amber 300 Perspex® acrylic, also known as Perspex® 300.
What is amber Perspex®?

Amber Perspex® is a great colour choice if you are looking for a clear/transparent amber tint.

Can I buy amber Perspex® online?

Yes! You can buy Amber Perspex® online here and select 'Amber 300 (X)' from the "Select Colour" dropdown.

Amber 300 Perspex® acrylic