Material:

Upper: Seamless knitted textile
Insole: Removable insole made of biomaterial
Outsole: Firm Ground outsole (2.5 mm outsole + 4 mm plugs)

What we like about these shoes:

Wide toe box for toe space
Thin and flexible outsole that provides excellent grip in terrain
Zero-drop sole (completely flat from heel to toe)
Incredibly light shoe weight

Fit and size advice:

Length: True to size - take your normal size in these but follow the size chart below
Width: Suitable for a narrow to wide foot
Volume: Suitable for a low to normal-high foot
Toe shape: Steeply sloping from big toe to other toes. If your second and third toes are as long as your big toe, you may need to take a size larger to accommodate the side of your little toe.

Vivobarefoot Primus Trail Knit FG barefoot shoes are a popular trail shoe perfect for trail running, outdoor activities, hiking, or frisbee golf. It has an outsole that provides excellent grip even on rocky, uneven trails. The upper is made of a knitted textile that is seamless and very comfortable against the skin. The material is airy and well-ventilated, making the shoes perfect for warm spring and summer days. The Primus Trail Knit can be adjusted for a good fit thanks to the quick-lock lacing - you get a tight fit around the ankle while the toe box has plenty of room for toes to move freely.
Care instructions: Hand wash the shoes with products like Collonil Bamboo lotion and regularly spray with Collonil Protect & Care to extend durability and maintain the water-resistant membrane.
Size chart
Note that Primus Trail Knit is available in both men's and women's models. The only difference is that the women's model is slightly narrower while the men's model is slightly wider. Men with narrow feet may opt for the women's model, and women with wide feet may choose the men's model.
Here's how to choose the right size: Measure your foot. Place the heel against a wall and measure to the longest toe. This is your foot measurement. Add 0.6-1.5 cm to this measurement to determine which size to choose. Keep in mind that when training with the shoes, your feet warm up and swell slightly, so ideally, choose closer to 1 cm in extra space, or a bit more. Check the size chart below (we have measured the insoles here at Widetoes).
Example: Your foot measurement is 26.2 cm. Then choose size 41 (27.2 cm) so you will have 1 cm of extra space.
Size chart

Size 40: 26 cm
Size 41: 27.2 cm
Size 42: 28 cm
Size 43: 28.5 cm
Size 44: 29.5 cm
Size 45: 30 cm
Size 46: 30.5 cm
Size 47: 31 cm