Hi Linda,
Thank you for shopping with us, and for taking the time to leave a review.
The canvas you have purchased is called 'Single Thick'. They are 18mm deep. The 'Double Thick' canvases are 38mm deep. There is a bit more information in the product description of each canvas on our website if you are unsure.
This naming protocol is explained in our Art & Inspiration Blog - you can copy this link and paste it into your browser to read more:
https://www.artshedonline.com.au/how-to-choose-your-canvas-understanding-the-difference-between-types-of-canvas
If you would like to exchange the canvas, you are welcome to do so, please contact us on 1300-785-406 or by email to customerservice@artshedonline.com.au.
Thanks.
