Silver Bar is an item in Postknight that is used in trading to obtain pieces of equipment when shopping at a Merchant's shop or to interact with love interests.
Silver Bars are very obscure items when compared to other items, having the inability to be dropped by any enemy from any area or as loot from chests. Their only source is from trading and relationship gifts, therefore they are obtained from Merchant's shops of Griffondell and Caldemount which often stock up on Silver Bars, while Asteria can provide all three types of bars.
Silver Bars are resident to a small subcategory of items: trade items. That being their only purpose is to be used to trade for different items to aid the player in their adventure. Similar to the lower tiered Copper Bar, it is used to unlock the equipment pieces and allow the player to grow alongside the difficulty curve that the game naturally presents. The Silver Bar unlocks the third and fourth tiered sets of equipment.
Unlike Copper Bars however, the option to trade up for the next tier of bar, the Gold Bar, is replaced by the option to trade simple Silver and Gold Ore alongside coins in order to get Gold Bars.