Here's a stylish Modernist 1973 hallmarked Sterling Silver bracelet... perfect for her birthday.
The bangle is typically early 1970s - with a Modernist simple straight shape and Brutalist/retro inspired geometric texture. It's fully hallmarked inside: 'MP' (Maylin Products, the maker), then an lion and lion head stamp for London sterling silver, and the italic date letter 'S' for 1973. It is also marked with 'Nymph' (the line of bracelets) and 'Brit. Patent No 1052231'. The silver is British 925 quality grade. Look at the retro linear pattern - it has diagonal cuts, machine cut, alternating between fine lines and shiny lines, which catch the light beautifully. 
It's around 17cm long inside when fastened, 11mm wide, and forms a 5.6cm x 5.6cm circle - a female adult sizing. Please check that it should fit you (not adjustable). It weighs a decent 20 grams (solid silver). Slimline, flat and elegant, this would suit a more petite wrist. It's not hinged but opens out slightly if needed - a simple design that opens and locks together beautifully. There's a very fine safety chain holding the two halves together.
Great condition. Looks beautiful on. Not quite a perfect circle. Very presentable, simple, classy, retro, and a perfect retro gift idea.
Includes P&P to the UK. Comes in a simple presentation box.