We develop a theory of motivic spectra in a broad generality; in particular 1 -homotopy invariance is not assumed. As an application, we prove that K-theory of schemes is a universal Zariski sheaf of spectra which is equipped with an action of the Picard stack and satisfies projective bundle formula. CONTENTS TONI ANNALA AND RYOMEI IWASA A.3. Constructions of -monoidal structures 41 A.4. Day convolution 42 A.5. Smashing localizations 43 References 43 1.3.4. Definition (Lax c-spectrum). Let S c be the free commutative algebra in Σ generated by F 1 (c). For an ∞-categoroy presentably tensored over , we define Sp lax c ( ) := Mod S c ( Σ ) and call it the ∞-category of lax c-spectra in . Then Sp lax c ( ) admits a presentably symmetric monoidal structure in a canonical way and Sp lax c ( ) is a presentably tensored over Sp lax c ( ). 1.3.5 (Adjunction). We consider the following adjunctions: -The adjunction (F, U) together with S c ⊗ − induces an adjunction F c := S c ⊗ F : ⇄ Sp lax c ( ): U. Then F c : → Sp lax c ( ) is symmetric monoidal and F c : → Sp lax c ( ) is -linear. -The adjunction (s + , s − ) induces an adjunction s + : Sp lax c ( ) ⇄ Sp lax c ( ): s − . Then s + : Sp lax c ( ) → Sp lax c ( ) is Sp lax c ( )-linear. 1.3.6. Lemma.