Custom built single speed beach cruiser 

Spec’s on the bike;
Size - 18”
Frame - Hi-tensile steel
Fork - Hi-tensile steel unicrown
Shifters - N/A
Cassette - Single speed 17 teeth
Crankset - Shimano FC M400 170mm with 48t chain ring
Wheels - Araya VP 20
Hubs - Exage HB-RM50
Tires - Kenda K847 (semi-slick center section that provides lower rolling resistance and raised side knobs for off road cornering traction)
Handlebars - Steel
Saddle - Everyday extra wide w/comfort springs
Seatpost - 25.4mm
Brakes - Tektro linear
Headset - 1inch steel
Single speed gear ratio considerations;
For flat places, a ratio of 2.6 to 3.0 is ideal for most people. The lower value of this range, with a cadence of 90 rpm, will allow you to ride around 30km/h, while the upper of the range would provide 34km/h. If you're just starting out on your adventure on a single speed or fixed gear bike, a gear ratio of around 2.7-2.8 will be ideal.