The Neutron Nano Mini Marker is a sick little disc from MVP. They're great for marking the lie of your disc, throwing into a bucket for random dubs, and for reminding yourself that you love MVP plastic. A mini is one of the must haves in your bag for a round of disc golf.
They're made of the same Neutron plastic that you're driving with. A little hint about these discs in case you have to throw them for any length of distance is that they're very understable.
It's up to PDGA standards for mini requirements so you can use this in your local C-tier all the way up to a national tour event. The price is great on these little discs because you'll be using it for years to come.