Lutron brand dimmers typically work well with Besa products, though most other brands are acceptable as well.  But more important than the brand of dimmer is selecting the correct type of dimmer to ensure compatibility.

An incandescent dimmer is suitable for use on all Besa products described as incandescent.  This type of dimmer can also be used on halogen fixtures that do not employ a low-voltage transformer.

An electronic low-voltage (ELV) dimmer is suitable for use on Besa products that are rated at 12v and employ a low-voltage electronic transformer.  This also applies to Besa monorail equipped with electronic transformers.

A magnetic low-voltage (MLV) dimmer is suitable for Besa monorail equipped with a magnetic transformer.  Use of an MLV dimmer with Besa product equipped with an electronic transformer will damage the transformer.