Neuropixels probes can be implanted chronically and carried easily by rats or mice.
On a mouse, an entire implant with steel headplate, acrylic, probe, and 3D-printed enclosure weighed less than 3 grams. The probe was implanted without a microdrive according to the method of Okun et al. 2016. The stl file for the 3D-printed enclosure can be found here.
A holder that can be used for inserting the probe can be seen in the image below. The holder is available from Fine Science Tools (1837444 Moria MC44 Bulldog Clamp Curved 35 mm), and a custom blue plastic piece was attached. Photo (rotated by 90deg) and holder design by Armin Lak.