Observation Details
The filter buttons have no accessible name but are "labeled" by their text and/or image content.
Remediation Notes
The buttons MUST be user accessible interface components. Ideally, use a native semantic HTML <button> element for the filter button, <fieldset> including <input type="checkbox"> for the "direct manufacturer filter" buttons, and explicit labels to go with them. As is, there is neither a programmatically determinable connection between the "labels" and the buttons, nor does the buttons have any accessible name, let alone one including the label.
Please (also) refer to observation 1.3.1 Info and Relationships – "Semantic HTML" for general remarks about the use of semantic HTML.