The 10K solid gold handmade 4mm diamond-cut rope chain necklace, from Apples of Gold Jewelry, is available in 20" to 30" length and includes industry standard lobster claw clasp.
Once diamond-cutting is applied to the 4mm rope chain, actual measurement will be 3.75mm due to diamond-cutting.
Also available in 14k solid gold, shown below.
Gold weight varies based on length:
20 inches - approx. 19.28 grams
22 inches - approx. 21.20 grams
24 inches - approx. 23.15 grams
26 inches - approx. 24.27 grams
28 inches - approx. 27.55 grams
30 inches - approx. 28.77 grams