Robux knives in MM2 usually stay offsale once the event or sale ends , so their direct purchase window is often short and varies by item. If you mean a specific knife like Heartblade, it was sold as a gamepass for 1,699 Robux and later went offsale, so trading became the only way to get it.

Quick scoop

  • Some Robux knives are available only for a limited release period.
  • After that, they can become offsale and stop appearing in the shop.
  • How long they stay on sale depends on the specific knife, not a fixed MM2-wide timer.

What this means in practice

  • If a knife is tied to a gamepass, it can disappear permanently from direct purchase once the developer removes it.
  • Once offsale, the item may still circulate through trading if players already own it.
  • For current value and availability, trading-focused MM2 lists are the best public reference point.

Example

Heartblade is a good example: it was sold for Robux, later went offsale, and by June 2026 it was being traded rather than bought directly.

Bottom line

There is no universal time limit for “Robux knives” in MM2; they stay available only as long as that specific release is kept on sale by the game.