指节套环 （中国：指节套环；**：手指虎；马来西亚：指虎，粤语称为铁莲花）是一种套在手指上的攻击性武器。

在****，持有和贩售金属制的手指虎是非法的。根据《枪弹药砲刀械管制条例》详载，手指虎是为刀械类的一种（第四条），非经中央主管机关许可，不得制造、贩卖、运输、转让、出租、出借、持有、寄藏或陈列（第五条）。

根据《香港法例》第二一七章，如无合法权限或合理辩解，任何人在公众地方持有「铁莲花」即被列为「藏有攻击性武器」，一经定罪，最高刑罚判监三年。

在日本一般的刀具店，可以合法的购买指节套环。但《轻犯罪法》另有使用规范。

Brass knuckles, also sometimes called knuckles, knucks, brass knucks, knucklebusters, knuckledusters, or a classic, are weapons used in hand-to-hand combat. Brass knuckles are pieces of metal shaped to fit around the knuckles. Despite their name, they are often made from other metals, plastics or carbon fibers. Designed to preserve and concentrate a punch's force by directing it toward a harder and smaller contact area, they result in increased tissue disruption, including an increased likelihood of fracturing the victim's bones on impact. The extended and rounded palm grip also spreads across the attacker's palm the counter-force that would otherwise be absorbed primarily by the attacker's fingers, reducing the likelihood of damage to the attacker's fingers.