Topic: Shield of shield & Bow of the uncanny marksman(low level magic items)

I have been concocting a number of low level magic items to hand to my low level players. I aim to make them intresting for my players while not being OP at their level. These are thelatest two i have come up with.
Shield of shield

Family: Armor and Shields
Category: Armor
Subcategory: Shields
Cost: 7 days casting shield on a descent quality steel shield
Weight: 10lbs

The shield of shield is a common type magic item. it Requires attunement to wear and works as a regullar shield with only one difference. Once between long rests the wielder can use the sorcerer spell shield without expending a spell slot. See the rules for the use of the shield spell in the player handbook.

Bow of the uncanny marksman

Family: weapons
Category: Simple Weapons
Subcategory: Ranged Weapons
Type: Piercing

Damage medium: 1d8
Critical: 20

Cost: A 4 feet long Ent branch, a bowstring and 50 years of your life
Weight: 3lbs

The bow of the uncaany marksman has been crafted from the branch of an ent and has kept a reduced form of consiousness. It help its wearer to correct small mistakes in their shooting style thus helping them to shoot ore accurately. The bow gives a +2 bonus on attack roll made with it. In order to benefit from this effect the wearer must have fired at least tree shots with the bow. The item does not require attunement but as said before the wielder must shoot tree times before the attack bonus aplies. The dammage it deals is considered non magical as it merely helps you to aim better.

DM: to your discretion you can allow the bows attack bonus raise together with the caracters level. It is advised to do this if the weapon is used frequently by the PC owning it. It would be explained by the bow gaining new experience from being used by the PC.