This is the 11861st most frequent Russian word.
запасных
"Spare" or "reserve" (genitive plural form).
In this sentence, 'запасных' (spare) is used as an adjective to describe items kept in reserve or extra for potential use.
У меня есть несколько запасных батареек для камеры.
I have some spare batteries for the camera.
Here, 'запасных' (substitute) is employed as an adjective referring to players who are not a part of the starting lineup but are available as replacements.
Запасных игроков вызвали на поле во время матча.
The substitute players were called onto the field during the match.
In this case, 'запасных' (spare) indicates additional items carried for backup purposes.