I'm having a play with MAC filtering on a Cisco SG300 switch. Just struggling to work out exactly what this means from the help.

Destination MAC Wildcard Mask--Enter the mask to define a range of MAC addresses. Note that this mask is different than in other uses, such as subnet mask. Here, setting a bit as 1 indicates don't care and 0 indicates to mask that value.
If I set it to 1 does that mean it will match those bits in the MAC address field or not? The "don't care" to me means that it may or may not.
Its very ambiguous from my mindset.